Is one allowed to receive an organ transplant from a non kosher animal?

If one receives an ovarian transplant, who's children are they?

If one transplants a head or a brain, who are you?!

If a person didn't have a heartbeat and comes back to life after CPR, did you save a life or revive the dead? Do they need to remarry their spouse? Did their children inherit their assets?

When exactly is the moment of death?