Honestly, we can know this how?
Uhh. Basic Magic Theory?
Intellego Animal works on Animal. Intellego Corpus works on Corpus. If you cast an Intellego Animal spell at a target which is currently not Animal, the spell won't work. Sure, it's possible that werebeasts require both Corpus and Animal, but when Sophronia followed her nose and saw a big redhaired woman picking bone chips out of her teeth, it may have occurred to her that the InAn(Co) worked where the initial InAn failed because Sinmore was a Corpus target at the time the spells were cast.
This is why I find this particular story just completely nonsensical.
Heck, Sophronia could ward Sinmore for every night of the full moon, spontaneously, without fatigue. Done.
"I doubt my ward would be of sufficient power to contain her, but with so little time left I don't know what else we can try. I'd only be able to create a ring of maybe third magnitude. Any other ideas for what we might do tonight?" Attravere inquires while walking toward Sinmore's location.
Warding a non-magical beast is not the same as warding a 0 might magical beast.
"Ward Against the Curious Scullion" is a ReCo10; an equivalent ward against mundane beasts would be a ReAn10. In this case, since the beast has an MR 0 (which is not equivalent to no MR) it does need to be cast with at least 1 penetration.
Ward Against the Curious Scullion has been errata'd and is :
Ring and Circle Ward Examples (p. 104): Change the level of Ward Against the Curious Scullion to 30, and replace the calculation with (Base 15, +1 Touch, +2 Ring). Change the level of Ward Against Mundane Intrusions to 50, make it a Ritual, and change the level calculation to read "(As Ward Against the Curious Scullion, +4 requisites)".
Again, I ask how I/we can know the beast is magical. Is it? IS it a guess? Would it also be a reasonable guess to require corpus?
I will, again, suggest that after less than a week of becoming active in the saga there are problems with the way this has unfolded. I was just getting used to Sophronia and what was going on, and in the intervening time she's discovered she was in a love triangle, insulted Voluntas, has no hope of being able to manage using the lab she's been assigned without significant warping and only a season to figure it out. We've also zoomed from spring to winter, with no reasonable chance for Sophronia and Sinmore to have resolved the issues between them. You've made a decision that you intend to resolve this a certain way, very well. Allow it to unfold. However, I cannot reasonably provide a good answer to Attravere or anyone, and it just seems odd. None of this is important to me as a player, anymore but it is inconsistent storytelling at best. If you'd said, hey you need to take care of some stuff. I could then go, oh yeah, can you give me a hint? If I said, oh, yeah, I'm going to let Sinmore handle it and come what may, that'd be different.

Ring and Circle Ward Examples (p. 104): Change the level of Ward Against the Curious Scullion to 30, and replace the calculation with (Base 15, +1 Touch, +2 Ring). Change the level of Ward Against Mundane Intrusions to 50, make it a Ritual, and change the level calculation to read "(As Ward Against the Curious Scullion, +4 requisites)".
@(£%%&@)(@)(*(&!
And here we have EXACTLY why the entire Wards thing is COMPLETELY FREAKING STUPID. It's a level 30 spell to ward against a COMPLETELY MUNDANE PERSON, but it's only a level 10 to ward against a MAGIC BEING with 10 might? AYFKM?!?!!? headdesk
I am this freaking close to throwing my 5th ed books out the door and just going whole hog 4th edition.

Again, I ask how I/we can know the beast is magical. Is it? IS it a guess? Would it also be a reasonable guess to require corpus?
I don't get what you're asking. The beast is magical insofar as it's someone who has initiated the Arts, and therefore has Form Resistance, even when denied her Parma. Lycanthropy can change Sinmore's shape and temporarily suspend her mental capacity, but it doesn't remove the Gift, or the fact that her Arts are opened. It doesn't affect her Parma, either-- it's just coincidence that the full moon rises exactly at the time her Parma normally goes down.

However, I cannot reasonably provide a good answer to Attravere or anyone, and it just seems odd. None of this is important to me as a player, anymore but it is inconsistent storytelling at best. If you'd said, hey you need to take care of some stuff. I could then go, oh yeah, can you give me a hint? If I said, oh, yeah, I'm going to let Sinmore handle it and come what may, that'd be different.
I apologise for what you're interpreting as inconsistency.
I have been frustrated at the general lack of follow-through on any number of hanging threads. There's a whole mess of things totally unresolved, where players seem to just assume that because they said they'd do something about somesuch, and then don't ever post about it or mention it again, that loose ends will somehow just automagically take care of themselves. Characters have never bothered to establish sancta, there's Sinmore's lycanthropy, two magae vanishing under highly suspicious circumstances, a brilliant apprentice with no parens, major warfare right in the front yard that no one does anything about until they literally show up on the doorstep, a giant demon escaping from the same ancient prison one of your parentes died in-- and everyone's content to go home, say "we should do something about that," and then they never do.
This was one of my attempts to remind people that "out of sight, out of mind" won't work. This particular prod was aimed at Sinmore, not Sophia.
Because some of those loose ends everyone's been content to let lie, will have catastrophic results if continually ignored.
You and I have commiserated over these things before.
That your aiming at Sinmore would be fine, but I'm tangentially involved in that (you named her IC). I took a few months off from this saga. You threw out a warning for players to have stuff ready to go before the goblins showed up. Throwing out another warning for something like this or any other issue is a good idea. Yeah, it's meta gaming, but it's also PBP. Your not getting full attention like in tabletop. It's easy to lose sight of details, both as a player and an SG.
This isn't a reminder, this is a full fledged bonk over the Head with your SG cudgel. Sometimes players forget stuff you think is totally obvious.

When he goes to remind Cygna about an hour before evening he'll see about whether Iapetus, Sinmore or Sophronia might have changed their minds and be joining them that night for the watch.
Hmm, don't remember being invited along. Must have missed that post in the thousands that occurred today.
Iapetus has been spending time getting the Lizard of Sheepdoom settled in somewhere, while simultaneously trying to get it to behave properly. Like not pouncing and licking people to show how well-behaved it is by not eating them. Since the thread moved on while I wasn't looking things over, we can assume he has something planned involving magical things, perhaps elementals, dragons, or kidneys.
The dragon will calm down after a few weeks of regular meals and real live affection.
The Mercer House gets an inquiry as to the status of Dinas Emrys -- apparently a couple weeks after the drake came home with you, the entire hillside got blown up. Completely immolated.
(Seeking to continue things as they were to some degree... seemed almost like there was a bit of Magi being on the same page there for a bit, even if we may not be able to do much immediately to stop Sinmore from doing more damage this evening.)
Attravere will question Sinmore outright once they reach her, it should be clear that Sophronia's word isn't being doubted, but that Attravere wants to hear it from Sinmore herself.
"So you're the one that destroyed the sheep. Why didn't you tell us?" Attravere demands.
Attravere plans a trip to visit Duos Flumen within the coming week (presuming there isn't something that massively delayed them).
He'll arrange a request for hospitality a few days in advance.
[color=red]"No, she isn't," Cygna says. [color=red]"The monster that she becomes under the full moon is. Luckily, she won't be able to restore her Parma before she changes...but she's still under the same protection that all of us are under the Oath. Unless I'm sorely mistaken, we should be able to ward you with an Animal ward, with penetration to bypass your innate resistance." ((Arya, correct me if I'm mistaken, but I do think that we just need an ReAn since she has no Int as a were-gulon.))
[color=red]"But we're going to need your help, Sinmore. We haven't done enough to help you, and for that, I apologize. What have you tried so far, to control the beast? And what do you think needs to be done to control it better?:

Attravere plans a trip to visit Duos Flumen within the coming week (presuming there isn't something that massively delayed them).
He'll arrange a request for hospitality a few days in advance.
Cygna will travel with Attravere as she said, and will try to make arrangements with her mater for a nice get-together and dinner.
Gruis is happy to arrange for hospitality for your group at Duos Flumen.
Before you leave, Leona tells Cygna that she could teach her to tend her beehives, which would provide an enormous amount of wealth for the covenant should they re-establish old trade relationships for selling honey (which is incredibly rare).

Gruis is happy to arrange for hospitality for your group at Duos Flumen.
Before you leave, Leona tells Cygna that she could teach her to tend her beehives, which would provide an enormous amount of wealth for the covenant should they re-establish old trade relationships for selling honey (which is incredibly rare).
Cygna would like that. Kills two birds with one stone...although that might not be the best metaphor, all things considered .
Not sure where to fit that into her Advancement, though, for 1221. If she has to, she will (I guess) have Leona Teach her Profession: Beekeper(?) instead of going to Hebrew school. Beekeeping would be of greater benefit to the covenant as a whole than learning Hebrew.

Attravere plans a trip to visit Duos Flumen within the coming week (presuming there isn't something that massively delayed them).
He'll arrange a request for hospitality a few days in advance.
Iapetus wouldn't think to ask, because he isn't a thoughtful sort usually. However, if invited, he would gladly accompany them just to go meet more people.

Iapetus wouldn't think to ask, because he isn't a thoughtful sort usually. However, if invited, he would gladly accompany them just to go meet more people.
You're going to have to play Deiectus.

Cygna would like that. Kills two birds with one stone...although that might not be the best metaphor, all things considered
.
Not sure where to fit that into her Advancement, though, for 1221. If she has to, she will (I guess) have Leona Teach her Profession: Beekeper(?) instead of going to Hebrew school. Beekeeping would be of greater benefit to the covenant as a whole than learning Hebrew.
She could do it for a covenant service instead of copying spells. It was a Legendary income source before, and now has ceased. If she gets up to basic proficiency, she can ramp up the income source back to its original level in short order (one season per year would maintain it).
"So you're the one that destroyed the sheep. Why didn't you tell us?"
Sinmore turns sharply at the accusation then suddenly realizes that there are a few magi confronting her. Her initial angry glare becomes a chastened and embarassed one after a few seconds. Finally she brushes a lock of her flaming red hair out of her eyes and shrugs.
"I didn't realize it was that much of a secret. Thought you of all people knew, ye were there the first time it happened."
"Oh really?" Sophronia turns and regards Attravere closely. "In any event, once we became aware you should have been suitably disciplined enough to control your condition. If unable to do so, ask for help. I know of a brother Tremere who is a lycanthrope[1], indeed his pater makes it a point to take on Gifted lycanthropes, but his entire modus operandi is to ameliorate the most egregious aspects of the condition. So now the question becomes, what are you going to do to repay us? Rest assured if additioanl covenant service is necessary for you to repay the debt, I will endorse that fully and vigorously. IT seems we must now micromanage your condition, since you appear unable or unwilling to do so. What magnitude resistance do you possess to corpus?"
[1]I'm basing this on a Tremere I made for A New Home, feel free to strike this, but I can't imagine that there aren't any Lycanthropic Tremere.