Pokémon bred from illegitimate Pokémon are also illegit. I know some people will disagree with me, but my policy is that, if a method *can* be used to obtain impossible Pokémon, then any Pokémon obtained using that method is illegitimate. By your statement, Dream Ball Rowlet is legal.
In any case, despite being event-exclusive, HA Torchic really isn’t all that rare. Just go onto any trading forum and offer something for it, like another HA Pokémon, or a Bottlecap. There’s really no need to resort to hacking.