Along these lines, also note that the house rules for Initiations prior to game start make the smaller Inner Heartbeast Initiations much better to do after game start instead of before game start since you can get them at 1/season with no Flaw at that point.
And - since I didn't see it noted above, though you probably know - for many categories you'll need to record three sets of Abilities, one for each of human, Outer Heartbeast, and Inner Heartbeast.
Thanks.
Thanks for the advice ... and apologies for a bit of a stall in the development of my character. In my professional life I'm a teacher, and it's grading time! Which is exciting, and time consuming. I do hope to turn my attention back to this as soon as I can.
Cheers.
Alright, I'm working on taking my character in a new direction. He'll still be an Animal specialist, but now a member of House Bonisagi, interested in pushing Hermetic limits by exploring Bjornaer magi's relationship with their Heartbeasts and other zoological phenomena. As was suggested, I'm taking a more detailed approach to his background, drawing from Guillaume's expertise 
His early life and the beginning of his apprenticeship are explored below, and more will follow. Thanks in advance for comments/questions/etc.
Herriot ex Bonisagus
Cormac never knew his parents and spent his early days in a Hibernian Monastery. His father was an erstwhile Welsh mercenary, part of the Henry II’s invasion of Ireland, and his mother an Irish peasant girl who died in childbirth. The monks took Cormac in and put him to work on their farms as soon as he was able. Natural gifts with animals soon emerged, along with a keen analytic mind. As he approached his tenth year, the animals under Cormac’s care began to manifest bizarre qualities. Two-headed calves were born, nanny-goats sprouted horns, and one foal sprouted the mythical wings of a Pegasus. The monks were unable to ascertain any Infernal influence over young Cormac, but were nonetheless relieved when a cloaked stranger offered to take the boy from them.
Cormac began his Hermetic apprenticeship under Felix Bjornaer, a Harmonist and skilled Hermetic diplomat, at the Hiberian covenant of Ashenrise. Felix encouraged Cormac’s natural talents with animal magic, noting with pride the youth’s intelligence and aptitude for learning. Cormac also maintained his Christian faith, instilled in him during his time at the monastery. In particular he was intrigued by stories of Genesis, the Garden of Eden, and Adam’s dominion over animals. He was very curious about Felix’s Heartbeast, and how the transformation defied the normal rules of Hermetic magic. That a person could be affected by both Corpus and Animal magic seemed curious, and further that Corpus and Mentem were separate, while Animal was a single form seemed to denote a flaw of sorts in Bonisagus’s theory.
As Parens and Apprentice undertook journey to Crintera for the Ritual of the Twelve Years, a chance encounter changed Cormac’s magical path. On the way, the pair spent a season at Durenmar, availing themselves of rare lab texts. Cormac encountered a record of the time spent by Ignatius Bonisagi with a group of Hedge Wizards known as the Beast Masters. They were able to summon animals in such a way that would seem to break the Limit of Arcane Connection. A second flaw in Bonisagus’s theory, also involving animals! Had the founder of the order considered the privileged relationship of animals to Adam? Was man’s relationship to animals actually limited by the divine rather than other Hermetic rules? Bursting with insight, Cormac ran to his master, who was deep in conversation with none other than Ignatius himself. After expounding his theoretical intuitions, Cormac was dismissed from the chamber. When later summoned to return by a grog, Felix quietly explained how Cormac was no longer his apprentice, and that Ignatius would now be his master. The pilgrimage to Crintera was interrupted, and Cormac would spend the remainder of his apprenticeship at Durenmar.
Characteristics: Int 5, Per 2, Pre -1, Com 1, Str -2, Sta +1, Dex -1, Qik 1
Virtues
Flaws
Early Childhood 0-5:
Irish (Religious Language) 5
Ireland Lore (Monestaries) 2
Athletics (Endurance) 1
Awareness (Alertness) 2
Brawl (Dodge) 1
Charm (Clergy) 1
Folk Ken (Clergy) 2
Later Life 6-10: 100 exp
Animal Handling (Horses) 3
Church Lore (History) 2
Concentration (On Horseback) 2
Bargain (Animals) 2
Ride (Speed) 2
Etiquette (Clergy) 1
Intrigue (Plots) 1
Apprenticeship 11-25: 300 exp
Artes Liberales (Ceremonial Magic) 1
Latin (Hermetic Terms) 4
Magic Theory (Animal) 4 +2
Magic Lore (Beasts) 1
Order of Hermes Lore (Magi) 2
Parma Magica (Ignem) 1
Profession-Scribe (Illumination) 1
Philosophiae (Ceremonial Magic) 1
Code of Hermes (Apprentices) 1
Theology (Biblical Knowledge) 1
Arts:
Creo 5 (15)
Intellego 5 (15)
Muto 5 (15)
Perdo 5 (15)
Rego 5 (15)
Animal 11 +3 (44*1.5=66)
Corpus 5 (15)
Mentem 5 (15)
Vim 1 (1)
149
Spells:
Opening the Tome of the Animal’s Mind InAn 25
Hunter’s Sense InAn 30
Commanding the Harnessed Beast ReAn 30
Shape of the Woodland Prowler MuCo(An) 25
Rise of the Feathery Body ReCo 10
The Call to Slumber ReMe 10
Scent of Peaceful Slumber ReMe 20
Years of Growth:
Days after his Gauntlet, Herriot ex Bonisagus received an intriguing letter. Felix, his old mentor, had been spending time among a Covenant of Ex Miscellanea Beast Masters in the northern reaches of the Loch Legan Tribunal, and would Herriot be interested in taking the opportunity to further his research. He jumped at the chance
Years of Growth:
Days after his Gauntlet, Herriot ex Bonisagus received an intriguing letter. Felix, his old mentor, had been spending time among a Covenant of Ex Miscellanea Beast Masters in the northern reaches of the Loch Legan Tribunal, and would Herriot be interested in taking the opportunity to further his research. He jumped at the chance to expand on his Parens’s preliminary research and to explore his own inclinations.
Although the Beast Masters were initially aloof from this polished scholar, Felix’s efforts enabled Herriot to begin to earn their trust. Much of their magic fell within the traditional bounds of Hermetic theory, but certain abilities, particularly their Animal Summoning, offered a conundrum. During an attack on the covenant by Norse raiders, Herriot witnessed the Beast Masters augmenting their summons with traditional Formulaic and powerful Spontaneous spells. Although Herriot was unaware of this at the time, Felix, acting as an agent of the Quaesitores, was investigating the Beast Masters for a possible connection to forbidden Diedne magic.
Ultimately Herriot spent five years among the Beast Masters, learning the ways of their particular brand of magic. As befitted his Bonisagus training, he attempted to integrate the insights affiliated with Animal Summoning into Hermetic Theory, particularly the teleportation aspect of Rego.
First Cycle (26-30) 5 Years, 20 Seasons
15 Seasons Advancement (150 exp + 30 exp Study Bonus = 180 exp)
1 Wasted Season
4 seasons in the lab
Vis Salary 21
Abilities:
Animal Summoning (Wolves) 4 (50)
Gaelic 2 (15)
Loch Legan Lore 1 (5)
Magic Theory 4 -> 6 (55)
Carouse (Power Drinking) 2 (15)
Rego 5 -> 10 (40)
I have a couple of questions regarding future development. How reliable/canonical are the spells on the Net Wizard's Grimoire considered? There are a few, especially in the MuAn and ReAn that I'm considering researching at some point.
Also, regarding breakthroughs. I'm not planning on having Herriot do any breakthrough research before his entry into the saga, but I believe this is the sort of thing he would be looking to do once he settles down in Andorra. There are two potential breakthroughs I was considering working towards. The first would be to have Animal spells affect humans in animal form, whether through shapeshifting or Hermetic magic. Obviously this effect is modeled on the Bjornaer Heartbeast mechanic. The second would be to combine the Arts of Corpus and Mentem. Herriot is intrigued by the fact that Animal can affect both the body and mind of beasts, while humans require two separate arts to achieve the same result.
What do y'all think of these as potential breakthroughs? Too ambitious? Not ambitious enough? Inquiring minds want to know!
I've found that, at the very least, the math on some of their spells is questionable, at best. I always take the spell description and recalculate from scratch...roughly half the time, you're going to get something different. The spells themselves seem to be okay, it's just that they're statted wrong.
They do seem ambitious enough. Is he going for A then B, or splitting time between the two?
I know that, even my own spells on the net grimoire, are off on (rare) occasion. Take the spell, recalculate/redesign it, make it your own. Or at least eyeball it.
BtW, I really love the Zoological Bonisagus approach. With a tad of Bjornaer backstory for spice. Hanging on to Felix as a mentor makes it even sweeter .
Good write up, and this leaves you room to grow 
Think animal, eat animal, drink animal
If I understand correctly, this is the Summon Animals Major Supernatural Ability possessed by Beasts Masters of HoH: S?
If so, you can't just put points into the ability, you must gain the major virtue. As far as I can tell, this is what your 4 seasons in the lab are for: 1 season, + 3 for a major virtue, possibly gained under the "Adventures" rules. This still costs you 30XP, which you forgot to compute, and, well, you should write out that you gain the virtue.
IMO, the best thing to do is to gain a Major Flaw. This'll cancel 3 of the 4 wasted seasons, which can then be translated into the 30XP you lack, leaving the rest of your XP allotment unchanged. Am I clear or confusing?
I'm exactly of PB's mind on this. If you look closely, you'll even sometimes see similar spells, with, for exemple, a lvl 20 spell being better than a lvl 30 one.
=> Consider them for inspiration, but don't trust them.
Perfectly fine IMO
You should look at Legends of Hermes for hints about combining Mentem and Corpus.
Note, though, that this may be a bad idea: Having mentem as a separate form means it can affect any intelligent being, while combining it with corpus could preclude that. It might be better to keep mentem as it is, but to allow Corpus to use the mentem guidelines for Humans.
Thanks for all the great feedback folks. I plan on advancing him quite a bit further so it's good to get the fundamentals right.
This is something I was wondering about. If I'm not mistaken, the major virtues are only required to take Supernatural Abilities during apprenticeship. After that they can be taught like regular abilities. I very well could be wrong on this, and would be fine with taking a major flaw to counterbalance the necessary virtue ... a couple of ideas are coming to mind. I may actually remove the Enemies flaw from his original makeup and add it in later at an appropriate time in the story.
In terms of the potential breakthroughs, I'm unsure which he would try to develop first. The way I'm planning the background, he's gathering information and knowledge that would form the basis of working on these breakthroughs later on.
It is possible to learn Supernatural Abilities, but so difficult that it really isn't worth it. The Source Quality you learn from, be it a teacher or a book even or whatever it is, suffers a penalty equal to the sum total of your Art scores and any other Supernatural Abilities. For you, that's -48, so you need a miraculous Quality 53 book and spend 53 xp to gain a score of 1 You have to achieve that score of 1 in a single season or the effort is wasted, but once you have it there is no more penalty.
But such a miracle book does not exist.
It takes 70xp to buy that Virtue without a Flaw (4 seasons & 30xp), 60xp with a Minor Flaw (3s & 30xp) or 40 with a Major Flaw (1s & 30xp). If they are a Mystery Cult, learning their cult lore can reduce the XP cost.
Yup.
That's why my advice is to keep it simple, put it under the single virtue you can gain through adventure (unless wanting to go the mystery cult route) and take a major flaw, leaving the rest of your character as it is.
For what it's worth, it seems to me the first breakthrough is more usefull. That way, when you see an animal, you don't have to wonder if it's a shapechanged human, you cast an animal spell and it works.
Likewise, it means you can change into an animal for a diameter, buff yourself, and become human again.
Mind you, you might run into the limit of Essential Nature there, which is precisely why bjornaer can be affected by animal spells :-/ But hell, at worst, you can still have funky spells from experimentations, maybe leaving you strange and interesting results, which is all research is about!
Very well, I'll take a major flaw to offset the gained virtue. Here's what I'm planning. First of all, instead of Enemies as his starting major flaw, I'll take Blatent Gift instead. Herriot will gain Enemies (Beast Masters) during his time with them. Apparently they don't like him magically experimenting on the summoned creatures 
Also, in terms of his later research, I think I will work towards The Fixer's suggestion of having Animal spells work on anyone in animal form. Toying with the limit of Essential Nature is certainly part of the plan. Whether or not the research bears fruit is another question ...
Good one, I like it
He could have tried to change them into human beings, graft them human parts to see if their humors could be affected by corpus, and if/when they become immune to mind manipulation through Animal.
Maybe he also tried to see how these could be summoned without an arcane connection? That's a big one, too: The beast masters summon animals without an AC. Could the same be done with humans? With spirits? With Elementals? Are these animals really animals, or just magical creations conjured from thin air? We should dissect them to see if they're anything special. And is the summons strong enough to override the beast instincts, so that it'll leap through fire, or eat its own paw to escape a trap?
This is all looking good 