I’m admittedly ignorant of all of this, but I’ll post my thoughts anyway:

If the AI is trained on their voice and that AI is available to other studios (like leasing or buying it from the original company), the one time payment for that actor’s work is a very very shit deal. They’re out of a job in multiple places or for multiple works now since it can be reused for many things.

I doubt that the contract says it’s only used for that one singular project. Companies are sneaky. However, I have not read said contracts so it’s a magical guess on my part.

Mmm, maybe. Affects also works as it means to influence. It’s subtle and context matters, but if AI is still changing things with their job then affects is the verb you want. If AI has changed their job and nothing further is happening then effect is the noun you want.

Probably something from The Flintstones.