Is what I've managed to put together so far. I decided I wanted to take advantage of the entry hazard Smeargle was bringing to the table though that might be a bit of a gamble as he is meant to Dragon Dance and Baton pass to Darmanitan. So I included Roserade so I can add upon Stealth rock if it gets set up and Flygon for his access to Dragon Tail.
I wasn't sure what pokemon to include for Zoroark's Illusion, or if I should switch Zoroark out with another pokemon.
EVs would also be great here.
Shell Smash > Dragon Dance on Smeargle. Spore should be enough to not let the defensive drops be a concern. Something to make the BP easier, like Magic Coat or Taunt, is also preferred in the last slot. Either find someone else to set up SR or just make do with Roserade (because it already can set up Spikes).
Definitely use Fire Punch on Flygon; since Flygon is fast, Dragon Tail's negative priority is a detriment here; IMO, it's better off on support sets.
Blastoise can be your Rapid Spinner for the team because Darmanitan is weak to Stealth Rock and Smeargle hates having its Focus Sash broken:
EVs: 252 HP/252 Def/4 SDef
You could disguise Zoroark as Roserade because Roserade discourages the opponent from using the Fighting moves that Zoroark is weak to (since Roserade resists Fighting).