To add on to what Vladimir said, if you're scared about Blaziken's High Jump Kick missing, go catch a Yanma since they have a chance to hold wide lens which will bring the accuracy to 99%
I would change "Flare Blitz" to "Blaze Kick" so you wont have to deal with two recoil moves and keep brave bird for coverage.
Gardevoir seriously doesn't need Shadow ball when you have a Cofagrigus and a Honchkrow (Dark has the same type coverage) You can replace it with "Charge Beam", "Grass Knot" (later on), "Draining Kiss" (paired with calm mind it's amazing recovery)
I would say you messed up with Honchkrow, you should've bred "Brave Bird" or even "Drill Peck" and "Roost" (for no recoil) onto it before using the Dusk Stone
You Should "Breed Hidden Power Fire" onto Ampharos along "Discharge" and "Dragon Pulse" for perfect type coverage. The last move is up to you, I don't recommend agility since it's in game and Cofagrigus can set up a trick room for Ampharos anyway. You can run "Light screen" for Utility, or "Cotton Gaurd" to tank physical hits, or T-Wave to cripple Others (you can pair T-Wave up with CG or LS for easier setup)
For Flygon. "Crunch" or "Superpower" would work for it. Heck even "Bulldoze" works if you need to slow someone down for the rest for the team
Cofagrigus would benefit from "Hidden Power Fighting" so he isn't so helpless on dark types and normal types
If you haven't you can do the whole IVs, EVs, and Natures thing to make the game that much easier.
Edit: If you do replace one of Ampharos's moves, replace power gem, Signal beam has a chance to confuse.