You're half right about the Pokeballs. They originally didn't show up as the right sort of balls but they do now. My Latias was caught in a Fast Ball and it didn't show up as anything other than a normal Pokeball in other gen 4 games, but now it's very much in a Fast Ball again!
Destiny knot passes down ivs from both parents, so you could use the 5-iv lucario and then try to find a female eevee with a special attack? (or you could even pre-breed and breed the lucario with a female eevee with special attack, get decent stats along with the special attack stat you need and then use that eevee as the parent?)
He seems like a pretty good deal and I think it'd probably be more difficult to try to find another foreign language parent with the right stats? Most people run sylveon as special though I've heard of people using it for a surprise physical factor.
I hope I helped and good luck with all your hunts!