does it really matter?
If the GM wants the villain to return the Villain will return unless the Heroes kill the Villain and keep the body in an extra- dimensional vault
even then it was an LMD ,clone, new robot body, etc if the GM wants
So all types are viable, but if the GM wants to bring that Villain back , where there is a will there is a way
I would take most as a vacation for the villain time will tell