Nice team you have here Z-Rex. :)
Trick Room is an awesome strategy in the current metagame that is mostly weather. If you're having issues with Gastrodon I'd recommend either giving Jellicent Toxic or replacing Smeargle with a Life Orb Heatran. It's slow enough to work in Trick Room and bulky enough to work outside of it as well. It also synergizes well with Scizor and can set up Stealth Rocks for you. Smeargle doesn't seem to provide much for you offensively, so Heatran can work out for you in that spot. Here's the set.
Heatran | Life Orb
- Stealth Rock
- Fire Blast
- Earth Power
- Hidden Power Grass
Modest
4 HP / 252 SpA / 252 Spe
Hope you consider this and gl. ^_^