[color=orange][font=sylfaen] AHAHA! I see a fault in your plan!

Tidus, Diglett should be confused because its not underground and yet he ordered to to stay there, so exploit that chance and hit it hard with a Razor Leaf! Brace yourself for Screech, and then afterwards run up to it and use Giga Drain to drain it. Slash isn't out big worry because of our Mighty Guard, so hit it hard and fast with a powerful Frenzy Plant! If Diglett goes underground on his first turn, then create a slightly weaker Earthquake by using Iron tail and slamming the ground.

Razor Leaf/Iron Tail (create Earthquake like thing) ~ Giga Drain ~ Frenzy Plant