What seperates these 2 from being the same? Would a live mouse or rabbit in a cage be considered a decoy and not bait since it can't be eaten or captured by it's prey?

Bait plays upon an animals survival instincts. Decoys mostly just for sex drive. Does come to them occasionally also for territoriality reasons. Decoys can be dangerous for the hunter during the gun season and are typically outlawed during that time in most if not all states.

Decoys for predators not for deer or turkeys.

Bait changes an animals patterns artificially and often unfairly.

Decoys fool an animal once. Seldom twice. decoys can't possibly change an animals daily habits the way bait can. The game won'tform a dependence on decoys.

I could name aseveral more obvious differences but this is an apples and oranges comparison.