I will start by answering the the second part first.
I don't personally know any purely vegan shifters, although there maybe a few out there. I did date a dingo-shifter once that claimed she was a pesco-vegetarian. I tried to point out that just because a cow could swim didn't mean it was a fish. I mean, I can purr like a kitten. Doesn't mean I'm a cat.
Guess you can imagine how that relationship turned out.
Fergus is your straight forward breakfast kind of guy. Normally it's just bacon and eggs (I won't tell you how much) with the occasional order of hash brown on the side. I do remember Saint making a quiche once and Fergus refused. He said it was too fussy to be breakfast. You know what that meant--more for me!
Thanks for the question.
Keep 'em coming!