I love you all to death (Just so I can smash bros with you) (SSBWiiU/3DS)

[NICKtendo DS]

It'd be really cool if he made an appearance, but I'm kind of worried now, what with Lucario being on the roster.

For Arceus' sake, don't. Lucario's confirmation does not affect the chances of Mewtwo.
God forbid if Mewtwo is cut from the roster again, it's most likely due to a new Pokémon being added to the playable roster, like maybe Zoroark. However, given Mewtwo's current position, it'd be weird to leave him out.

Also:
Teleport =/= Extreme Speed
Force Palm =/= Confusion
Counter =/= Disable
And a decent amount of A-moves aren't even similar.
The only thing they've truly got in common is their neutral-B charged projectile attack, and even those have notable differences.
The whole argument that Lucario is a Mewtwo clone is bullshit. Also note that Lucario is a veteran character who is only playable because people liked him in Brawl. Lucario in does not mean Mewtwo out.