I use legal hacks so I guess I can help you with this. The pokemon I use for battles are generated/hacked through a program, but all of them have legal move sets, IV's, EV spreads, and nature. Not too sure about RNG'd pokemon, but I don't think they classify as hacks.
RNGed Pokemon are generated by the game the same as any other random Pokemon you find, so no, they're not hacks.