A revenge killer is a pokemon that comes in after another pokemon faints and KOs the opponents pokemon. As for replacements you could try a m venasaur and see how it works. It actually might be pretty cool. I wouldn't recommend hyper voice sylveon as moon blast does plenty.
Scarf gar is a revenge killer. The gar your running right now is a sweeping gar. If you want to make him into a revenge killer then we could do that, but it might be worth your time to keep focus sash.
My family is buying a new car, so in awhile we should be good.