The Provencal Tribunal of 1221 has a quaesitor problem.
A tribunal is required to have three quaesitors sitting; the Presiding Quaesitor and two advisors (p. 64, HOH: TL).
In our saga we will have Beatrice, our covenant quaesitor Domitiana, and ... there is no good other candidate. There is a secret quaesitor who might step forward if required, but I'd rather avoid that.
In such a situation, it follows that Magvillus might send a fresh young quaesitor, or even a more experienced one, but the fact is that Beatrice is the only quaesitor with knowledge of local peripheral code and more or less has to be the presiding quaesitor for 1221.
The solution is simple. Not every single magus of the tribunal was named. There are probably more covenants too. There is space to fill things out as suits your saga. Can't nail every single chamberpot :d
Acting as an advisor seems the perfect role for the one you're thinking of, to me. He must have the Hermetic Prestige Virtue, authorizing him to act as Quaesitor, but he prefers not to do so. But the circumstances are unusual, and if there's no one else, that might force him to get involved.
We've considered this - a review of the established covenants suggests (but does not explicitly state) there are no other quaesitores at the published covenants. Yes, it's possible there's some small covenant of no particular influence or note with a junior quaesitor.
The quaesitores of the tribunal seem to have been concentrated at Castra Solis, three (Senex, Tibaut, Beatrice) with another, Augustus, at Tolose Paratge. There is another at Aedes Mercurii, who is unwilling to come forward absent a compelling reason. There's an ejected former member of House Guernicus at the Coenobium (Xiphos) we decided would never be approached to be a quaesitor.