Bullet Punch is fine on Lucario. Here is the moveset for Lucario off Smogon:
Lucario @ Life Orb
Trait: Justified or Inner Focus
EV's: 4HP/252 Att/252 Spe
- Swords Dance
- Close Combat
- Extreme Speed
- Ice Punch/Crunch/Bullet Punch
As you can see, they do include Bullet Punch in their list of options. You could also get rid of Swords Dance and give him 2 of those last moves and a Choice Band if you wanted to, so Bullet Punch is perfectly viable.
As for who you can breed it with Hitmonchan is the only real option, although Lucario is also in the Field egg group, so it can also breed with Smeargle.