There is a difference between the guidelines for CrAn and CrCo. Bring an animal back from the dead (CrAn 75), vs Raise the dead, to a point (CrCo 70). Not a big thing except for a small group of people who are Truly animals. There's some stories there. Do Bjornaer's have souls or are they completely of the Magic Realm? CrAn can create Magic Beasts. This would seem to imply that CrAn could bring Magic Beasts Back From The Dead. So what? Back from the Dead or Created New, there's a spell to cast and Vis to spend. Except for the Great Beasts of Bjornaers. They would seem to be nastier then their Might score would imply. Would an Arcane Connection be enough to "Raise them"? Man, the Bjornaer would be hard to beat in a War......
Pretty sure you couldn't bring a Bjorneaer back from the dead by conjuring its animal component. Well, maybe you could but the soul has still moved on and that part of him that was man is elsewhere.
If their soul was stuck here I am pretty sure that would represent a major weakness in their line and it would be expressly noted, and quite grim for potential members to realise after the ritual of 12 years their soul is damaged / lost.
That said, no reason stories cannot be created around Maga Bjorneaer who for whatever reason had this happen for some reaosnm and thier soul is temporarily stuck here linkde to its animal nature.
CrCo(An) and it would be ok 
Wolf bjornaer returned from the dead. You now have a nasty magical wolf in your hands, but not a bjornaer. IMS at least. The human component is not there. The "spark" or spirit that makes humans special is not there anymore.
Cheers,
Xavi