The Founders Familiars

Has there been any cannon on on what sort of familiars if any the founders had? I know that Merinita brought the practice to the order so she obviously had one. If Bonisagus had been the one to incorporate it then he should have had one. What sort of creatures would the other founders have bonded with.

I remember the following from the HoH series.

Bjornaer = None (of course)
Merinita = Stag
Tremere = (White) Wolf
Tytalus = Dog

I also seem to recall that Jerbiton had a Cat, but I may be mistaken (Serf's Parma).

Yes.
RoP:M p 70, Black Lineage "a prince of the Egyptian cats"
White Lineage is Mercere.

An Owl would have looked good on Bonisagus, or maybe Guernicus?. (Not that I have read that anywhere)

Mercere: white cat
Criamon: a spirit in the shape of a bird

Actually, a spirit that could take the form of a dog.
I seem to recall that Diedne had a tortoiseshell cat, but may be completely wrong on this one.

Verditius: None or Raven

Verditius only went to Durenmar at the very begining, but then refused to return after he'd learned the Hermetic basics. Not sure if he ever learned how to bind a familiar, or, if he did learn, if he did.

If he did, I'd argue for a raven, as he succeeded in the quest to find Wayland Smith with the help of such a bird.

Guernicus would have had an earth-related creature, as his first specialty was a Earth-Cult magus. A badger would be appropriate, I think.