No. First off, who are you harming by sexually contacting a corpse? Dead people don't think, they can't be harmed, they don't have feelings, and they don't have rights (if corpses have rights, trees and stones should have rights, too).
Bestiality, though... Well, it depends. If the animal is showing distinct signs of discomfort during the activity, it shouldn't be allowed, and if the person has some sort of STD, it shouldn't be allowed. If the animal is hurt in the process, illegal. If the animal isn't harmed or traumatized because of the event, it shouldn't be illegal.
As for human-human sexual interaction, humans are capable of saying clearly that they're okay with it, and consensual behavior should be fine. Although the death of any consent-givers should result in a negligence and\or murder charge.