Get Pikachu to use Agility right away, maybe use it twice, since it'll boost the speed of all party members.
Don't bother with orbs because it'll only work on Munna, though if she's giving you trouble go ahead and use one.
Get Emolga away from the Gigaliths since they have Rock moves; try and position him near Toxicroak (why doesn't Emolga have Acrobatics?). Virizion should be around the Gigaliths so just mass spam Magical Leaf, and Oshawott should be dealing with Chandelure. I'm pretty sure Toxicroak will have Dry Skin, so get Oshawott away from him. Deselect all your normal & fighting moves because they'll do very little damage on Chandelure & Gigaliths, and instead just go for STAB.
If Munna uses Future Sight, just move a square away and it'll fail.
Team attack could help in a last ditch effort, so try that out.