What about that move that Shuckle uses to average out the Defense or Offense of all Pokemon in play? That could help Smeargle, and hurt the foe, say on the switch after Spore.
Maybe: Spore, Baton Pass, Substitute, Power Share.
Also with things like that move that makes a target have the ability: Simple, that could be great in Doubles... *can Smeargle target itself? Imagine that with a Power-up move.
*ALSO, consider Transform on Smeargle. Ditto is better due to Ability, but Smeargle can Spore, Substitute, Filler [Reflect, Magic Coat, etc], Transform.