Questions and a To Do list:
The apprentice is a similar issue to what silveroak was facing. I don't want to bring in apprentices that are so tied to a master, and that are too advanced, either, for that matter. It may be that you need to rehome an apprentice or destroy his Gift in some manner. Consider the impact it will have upon you. We can make this issue as part of a starting off point when Elizabeth comes to visit you as a prospective professor at the school.
OK, so here's a way out: since there's going to be 2-3 years at the start of the saga before the teachers are ready to actually teach, Ancel can continue his training and try to squeeze in extra seasons (at the cost of his own development). When it's time to train students, he administers a slightly early Guantlet for his apprentice. After all, 15 year apprenticeships are merely traditional, not required by Hermetic Law. (c.f. Bjornaer who consider apprentices full members once they take on their Heartshape, or that Flambeau apprentice during the Schism War who was considered Gauntleted after 7 years after defeating some Diedne in battle) Trianoman Gauntlets are also straightforward -- send the apprentice to another Trianoma at a distant place to prove they can manage on their own. All she has to do is get there, and she's passed. That also gets her out of the school; we'll just assume she settles in another Tribunal. Perhaps back in Stonehenge, where she would've spent most of her apprenticeship.
It's a matter of Bonisagus pride to have a trained apprentice, so Ancel would prefer to see her on her way, even if it means breaking tradition. But given that he's at this school, he's clearly not averse to breaking tradition. Additionally, as a magus trained in the Rhine Tribunal, it also means he'd be Master status. (This doesn't mean anything outside the Rhine, but some habits die hard.)
But those 2-3 years of time are going to be focused on preparing the instructors to teach Hermetic Arts to more than one person at a time, it's a new Arcane Ability, among preparing the classrooms and possibly recruiting new apprentices. I mean [strike]Dumbledore has to go out and bring Tom Riddle to Hogwarts[/strike] someone has to go out and recruit these apprentices. It's not all that hard a job to recruit apprentices, and it wasn't going to be required of everyone... The point is that those 3 seasons are going to be heavily directed, out of those 3 years, you'll get one season of free time, probably and the rest is about setting up at the school.
I neglected this...
What kind of specialist and why? Honestly was thinking that these can be handled by the Tremere. There is a reason why I chose the Tremere and Transylvania. They simply have the ability to pivot the entire House (and the Tribunal) at the whim of the Primus. Poena sees a chance to make her mark, and she's committing vast resources to the effort prior to her retirement. In that end, she wants the school to be successful. House Bonisagus wants the school to be successful, too, but can't allocate nearly the level of resources, especially since Durenmar has been in steady decline and is prior to the new Prima is teetering on Winter.
I haven't done a history of the Order/Mythic Europe, I've been putting it off, because of work. But one of the things that's happened is that there has been a steady uptick in the number of Gifted individuals. Hedgies are also snapping them up more readily that Hermetic magi as magical resources are continually diminished by the encroaching urbane environments.
Re: limited free time
That's fine; if he has only one season free, then he'd spend it training his apprentice and would have no "free" time to study other things. To look at it in-character, he's got three things to juggle per year:
He's not going to see the 3 seasons a year as wasted or unnecessary time. This is something he's interested in after all, and he knows there's a large front-loaded investment of time to see it get started. He just happens to have this additional responsibility and duty to his apprentice and that means his own personal research gets squeezed out. But that's a call he'd be willing to make. This is no different from a parent who sacrifices for his kids by working long hours and dropping anything that isn't working or supporting the kids. It's only for a couple of years, after all, and within 5 years or so, he'll have a new routine of teaching and time for his own stuff. He's a magus; having a long view of things isn't as big a deal as it would be for a mundane without the benefits of a Longevity Ritual. 
From an OOC perspective, I'm perfectly fine if he gets zero XP for 2-3 years because he's so busy running around. By the end of it, Ancel will have a richer background for it.
Re: specialists
I was thinking that at some point in his career, he'd have picked up the usual entourage: a shield grog, maybe a scribe or a personal valet to handle all those mundane concerns. (Minor characters, basically.) It's not that big a deal, I was just wondering if I should just be looking at books and enchanted devices. (I have a list I'm working on.) If House Tremere is otherwise providing the mundane staff, then I'm fine with ignoring specialists.
Laterala, the assistant headmistress, has a team of Tremere soldaten at her command, any one of which can be assigned as a shield grog to a magus should they so choose. They all speak impeccable Latin.
As far as any other assistants you'd like to bring, get specific either in or out of character.
[size=150]Athena, Magical Owl Familiar[/size]
This is Athena after Bonded as Ancel's familiar and using the chargen advancement rule of 2xp per season unless directly trained by Ancel (see chart below).
Magic Might: 8 (Animal)
Characteristics: Int +2, Per +2, Pre -1, Com +1, Str -10, Sta +1, Dex +1, Qck +10
Three Cords: Gold +3, Silver +2, Bronze +1
Size: -5
Power Level: Grog
Season: Summer
Virtues and Flaws: Gift of Speech, Magical Animal, Wilderness Sense, Improved Characteristics, Gossip, Animal Ken; Busybody, Covenant Upbringing
Magical Qualities and Inferiorities: Gift of Speech, Improved Abilities, Minor Virtues (Improved Characterisitics, Unaffected by the Gift, Gossip, Animal Ken); Susceptible to Deprivation, Minor Flaws (Busybody, Covenant Upbringing)
Personality Traits: Owl +3, Busybody +3, Inquisitive +5, Loquacious +4
Combat:
Claws: Init +9, Atk +2, Dfn +15, Dam -8
Soak: +1
Fatigue Levels: OK, -1, -3, -5, Unconscious
Wound Penalties: –1 (1), –3 (2), –5 (3), Incapacitated (4), Dead (5+)
Abilities: Area Lore Cambridgeshire (home range) 3(1), Brawl (dodging) 2, Survival (home terrain) 3, Awareness (food) 4, Athletics (flying) 3, Artes Liberales (logic) 2, Charm (first impression) 2(8), Folk Ken (travellers) 2(10), Bargain (gossip) 3, Etiquette (magi) 2(6), Guile (knowledgeable) 3, Hunt (rodents) 3, Philosophiae (natural philosophy) 2, Stealth (natural areas) 3, Animal Ken (birds) 3, Wilderness Sense (find prey) 3, Magic Lore (creatures) 2(4), Faerie Lore (vis sources) 1, Order of Hermes Lore (personalities) 2(5), Magic Theory (Intellego) 3(4)
Natural Weapons: The Owl’s claws are Init –1, Atk +2, Dfn +3, Dam +2.
Bond Powers: Ancel may cause Athena to shapechange into human form once per day. This lasts as long as desired as the bond maintains concentration.
Bonding Score Lab total (InVi): Int (4) + MT (7+2) + In (11) + Vi (14) + Aura (7 at Durenmar) = 45 points (+3/+2/+1 score), 9 pawns of vis
General Abilities
Area Lore Cambridge +16
Charm +8
Etiquette +6
Folk Ken +10
Order of Hermes Lore +20
Arcane Abilities
Magic Theory +34
Magic Lore +4
[size=150]Aging Rolls[/size]
At 63 years of age, Ancel looks like a still-fresh 35-year-old. Huzzah for parens-created Longevity Rituals!
Invisible Castle Reference Links:
Assumptions:
Spreadsheet:
[size=150]Build Points[/size]
Build Points will be spent in decade-sized blocks for ease of calculation.
Summary
[table][tr][td]Decade the First
5 BP: 25 pawns of vis
44 BP: Enchantments
1 BP: Money (10 Mythic Pounds)[/td]
[td][/td]
[td]Decade the Third
5 BP: 25 pawns of vis
15 BP: Specialists (Servants)
30 BP: Books[/td][/tr]
[tr][td][/td][td][/td][td][/td][/tr]
[tr][td]Decade the Second
5 BP: 25 pawns of vis
44 BP: Enchantments
1 BP: Money (10 Mythic Pounds)[/td]
[td][/td]
[td]Decade the Fourth
5 BP: 25 pawns of vis
14 BP: Enchantments
31 BP: Books[/td][/tr][/table]
Details
Decade the First
Vis: 25 pawns of vis (5 used in Decade 2 for Longevity Ritual)
Money: 50 Mythic Pounds
Enchantments:
Decade the Second
Vis: 25 pawns (all used, plus 5 borrowed from Decade 1 for Longevity Ritual)
Money: 10 Mythic Pounds
Enchantments:
Decade the Third
Vis: 25 pawns (12 pawns used for Familiar)
Specialists:
With his growing duties and prestige, Ancel recruits and trains a number of skilled servants who assist him
(8 BP) Personal Valet with Profession Servant 8
(7 BP) Scribe with Profession (Scribe) 7
Books:
Due to his time at Schola Pythagoranis, Ancel develops a taste for academic knowledge and begins to collect some of the works of Robert Grosseteste (A&A p.139)
(10 BP) Philosophiae Tractatus: De luce (“Light”), Quality 10
(10 BP) Philosophiae Tractatus: De accessione et recessione maris (“Tides and Tidal Movements”), Quality 10
(10 BP) Philosophiae Tractatus: De iride (“The Rainbow”), Quality 10
Decade the Fourth
Vis: 25 pawns
Books:
Ancel continues collecting the works of Robert Grossteste and picks up a tractatus on Imaginem before he departs for the school.
(10 BP) Artes Liberales Tractatus: De Sphera (astronomy), Quality 10
(10 BP) Artes Liberales Tractatus: De lineis, angulis et figures (arithmetic), Quality 10.
(11 BP) Imaginem Tractatus, De Speciebus, Quality 11
Enchantments:
(4 BP) Clothe the Naked Form (CrHe 10), 1x/day; final level 10. This is a ring that Athena wears, Ancel's familiar. Shortly after developing the shapechanging power for her, he realized that Athena would otherwise be naked. In order to prevent the wrong kinds of rumours spreading, he commissioned this simple enchantment to provide Athena with clothing. (Spell is in MoH p. 58)
(10 BP) Cleansing the Room of Magic (PeVi 10), +10L for Penetration, +5L for 24x/day; final level 25. Casts Wind of Mundane Silence in the room. If a stress die + 10 doubles the effect, it goes down. Has +20 Penetration. Useful for knocking down students' magical pranks -- or a hedge wizard's minor magics. Takes the form of a candle that is lit to activate the effect. It immediately goes out as the effect takes place, acting as visual and metaphorical cue that magic has been snuffed from the room.
I haven't done my fine tooth comb on any of the characters yet, so this may not be the only thing that I comment on.
I'm thinking that this needs to have a fast trigger for it to be used most effectively. Items have generally the same rules for activating them as spells do, so while it might be possible to get this effect off on time, Ancel's Finesse and Quickness isn't really high and so an average fast cast roll is going to be an 8. A fast trigger on this would push it to 11. Going to 11 is always good.
I'm not familiar with the fast trigger effect for enchantments; it doesn't seem to be on p. 99 of the main book. Is there another book where this is detailed? (Alternatively, if this is a house rule, what's the level change?) If it's just a level change, I'll probably just reduce the number of uses if possible.
Sorry, it's from Houses of Hermes:Societates, page 33. It's a +3 addition to an item.
Heh, naturally it'd be a Flambeau-used effect. OK, I'll add it into both effects, which will be +10 levels of effects, or 4BP worth that I'll take out of the BP I was using for money that decade.
[size=150]Books Written[/size]
All books are Quality 12, some with questionably latin titles.
1230 - Vim Tractatus - Reading the Immaterium
1233 - Magic Lore Tractatus - De Magica Extra Ordinem ("About Magic outside of the Order")
1236 - Magic Theory Tractatus - E Pluribus Unum Theoria ("Out of Many (Magics), One Theory")
1239 - Parma Magica Tractatus - Why Trianoma Survived Meeting Flambeau
1242 - Magic Lore Tractatus - On the Organization of Witches
1245 - Vim Tractatus - Ars Longa, Hoc Liber Brevis ("Art is Long, This Book is Short)
1248 - Intellego Tractatus - De Motivis ("On Motivations")
1251 - Code of Hermes Tractatus - A Guide for Dealing with the Witch
[strike]1254 - Magic Theory Summa (Level 3) - Beginnings for a Beginner[/strike]
1254 - Magic Theory Tractatus - Principia Pro Incipientibus ("Beginnings for Beginners")
No summae and the quality level of the tractatus is limited to 11 (as per Covenants).
Even for books the magus wrote himself? These aren't purchased with BP, I listed those books separately. (Obviously Ancel can't benefit from these, as he wrote them.)
Forgive me, this wasn't big enough for me to read at ~7am in the morning. 
All of the tractatus are fine.
The summa is a problem because well, summae are problems, generally. And the level is 3, but his score is 5? That's not possible.
Actually, by the time he wrote the book, his Magic Theory was 7. I did keep an eye on that. (See third decade, particularly the chart. He wrote the book Winter 1254, and the last time he improved Magic Theory in chargen was the season before, so his Magic Theory was 7.) I can change it to a Tractatus with the same title.
For some reason I can't read today. I swear it said Magic Lore. Sheesh.
In any event, I want to stay away from summae, generally, which is why I said the following:
Now I said that because I thought players would try and bring summae with them, and I wanted to avoid that, but I never really dreamed that they someone would actually write a summa and bring it with them. 
Can I suggest you doing something else than this summa? You're going to find it... underutilized.