They are the same. I didn't notice anything in your back story about her being involved in Nigrasaxa in 1222, but I could be forgetting...
Not an accident Tranquillina chose her! 
But it is a very nice coincidence, that one of the few people Tranquillina would immediately get to talking to when she arrived at Mons Electi would be so well-suited to this role.
At first this deduction surprised me. But Moire has been around magi all her life, and is also a Clear Thinker; so I guess it makes sense that she would have some idea about wizards' sigils and be able to draw connections like this. Am I right in thinking, though, that a typical muggle (even a typical covenant resident) wouldn't connect these dots? I can definitely see some folk rumors spreading about Tranquillina connected to her Gift's effects and her sigil, but nothing precise...?
And on that topic - am I right that if Tranquillina wanted to suppress the nausea-inducing telltale of her spell, she could cast the canonical MuVi spell Shroud Magic the round before?
I think it was the momentary nausea that quickly passes. Not normal, especially when there's not any obvious reason for it, like a noxious smell or being in the back seat of a moving car. I've been nauseous enough to know that it almost never passes quickly. Plus, the effects of the Gift,which cause suspicion. Something weird happens, and you know there's a wizard right there, it's obviously the wizard's fault, right? 
I'm looking at the description for Shroud Magic, and it looks like it has to be cast either on a spell as it's being cast, or a spell that's been cast and is still active. Such as Aura of Righteous Authority. But, in a related vein, I was under the assumption that the sigil lasts for the duration of the spell and not just the moment it's cast. Is that not correct, or does it depend on the particular sigil? I can understand it being dreadfully inconvenient if someone with Aura of Righteous Authority had to spend the rest of the day making sure they knew where the bucket was, as opposed to someone who had white hair all day. Could be wrong, though.
Sigils can vary considerably...
And can have momentary or lasting effects. They always manifest in the spell in some way, or at some point. They can affect the caster or the targets. The only guideline is that it is never useful (unless there is an appropriate virtue) and doesn't impose major problems.
So, for example, with Fiona's La Petite Mascarade, having her hair turn white during the casting, while the body shrinks and reshapes itself, but then be whatever color she decides the Blanche form would have for the rest of the spell, that would be legit?
It can be as you wish, a moment or the duration of the spell, but it shouldn't be inconvenient, although higher level effects might become more inconvenient. For example, Ra'am's sigil typically gives the sensation of static electricity on the body, clothes clinging, and at high level have an accompanying buzz. Prospero mistook that for facility with lightning/Auram when he took Ra'am as his apprentice.
And thus did Alexei invent the Drunken Master School of Magic.
Invent? No, no hardly.
Perfect? Maybe. 
YES! Glue a strand of his hair to every chamberpot in the Villa, enchant them, so every time someone poops or pees in the pot, it dumps on Valerian!
Any random piece of shit ought to serve as a sympathetic connection to Valerian 
Random item: since I've recently had a relevant erratum pointed out to me, I put two and two together and realized that one of the lab texts in the Mons Electi library, Ward Against Mundane Intrusions, has the wrong level and hence bp cost (not to mention is now a ritual). What is a poor covenant to do?
Take a sharpie to the price tag and walk away non-chalantly?
I fixed the level on the wiki page, and put, under Cost, 7(10), so we know what we paid and what we should have paid, in case anyone cares about cost for stuff that's already paid for.
It's not a ritual. It's over 50th level and otherwise major spells that might be below 55th level that are rituals. IMHO, this isn't a ritual, just high level.
I expected this to happen but not while Valerian is stand there.
bows top JL
Touche
Not done, yet...
Two semi-related questions:
- What books (if any) do we have that are not covered by Cow & Calf? That is, what books can we trade copies of without having to track down the author (or his heirs) to get permission?
- Since we don't seem to have anyone at the covenant who can read/write/teach ancient Greek (Hermetic Greek), how do we go about getting one, and how difficult would it be?
ahhh. We have a teacher of ancient languages. Renaud made the effort to go to Paris and recruit a teacher of ancient Greek. It is how Korvin, Jacques and Isen learned it and read the fabulous book of Rego.
By my reckoning, 1223.3 is the first season of Tranquillina's residency at Mons Electi. Of course it's perfectly reasonable for Korvin to not have much about her on the tip of his tongue ... just wanted to make sure you haven't forgotten about her! 
It's possible that Tranquillina doesn't arrive there by the time Korvin has gone off to Dijon. What are her/your plans for her?