I suspect being in a dreaming wood gives a different perspective on the world, the same way being in an extremely high tower lets you see further.
So you are saying, her loyalty is irrelevant to benefit the Empire such as destroying the Necromancy College is irrelevant, her slaying of multiple vampires is irrelevant, the building of the Eye of Gazul is irrelevant, the creation of the rooms of Calamity which has already saved wizards in the College is irrelevant and so many actions which she has done is completely irrelevant in the decision making of those parties?
Yep. That person dies when their soul is consumed by a conflagration of dark magic. Just as dead as if the mind had been killed, or the body. Continuity of identity is something I don't think we ever get much of an inside look at? Like, a vampire talking about if they are the same person after the change...
On the topic of shenanigans, we'd be a vamp with a Ranald gifted Wolf presumably still attached to our soul as the most immediately obvious filter/tongs/blatant cheat in the event that the god juice now burns us.
Ok, this is an under discussed point in the whole Mathilde/vampire thing.
Wolf.
My suspicion is that there are a few possibilities:
1) He does immediately as his soul is consumed by the dhar vortex for fuel.
2) He is mutated by the in-soul dhar exposure to become a monster.
2a) A physical monster, like a chaos spawn
2b) a mental monster, where Mathilde displaces her hunger into him and he kills and drinks. Mathilde might be unaware of why she isn't hungry?
3) Wolf becomes a vampire in and of himself
3a) breaking the familiar bond.
3b) becoming a thrall
4) outside possibility, but the "good" parts of Mathilde's soul could use wolf as a lifeboat when the rest burns to dhar, setting is up for a quest where the enhanced familiar has to go kill the monster his old master has become.
5) remains a normal, god-touched familiar, now enslaved by a vampire instead of partner to a wizard.
So, all in all, wolf would be kinda screwed by Mathilde becoming a vampire, in my opinion.
Protect the fluffy boy! Refuse the blood kiss!