Tbh, this team REALLY sucks.
Gardevoir: For god's sake man, adamant is the worst possible nature for gardevoir, which lowers it's special attack. Modest & Timid are the 2 natures it enjoys most.
Gallade: He however, WANTS an adamant nature, and would appreciate slash being changed over to Close Combat.
Leafeon: I love this little guy, and should have a moveset more like this; Wish, Swords Dance, Baton Pass, Leaf Blade. Nature's actually good on her.
Swampert: Want's a relaxed nature and the following moves: Surf, Ice Beam, Earthquake, Stealth Rock.
Charizard: A lot of problems. The charizard I use, runs the following set: Dragon Dance, Flare Blitz, Thunderpunch, Earthquake and wants an adamant nature.
Jolteon: Also a good nature, but would like a few changes. Go with Thunderbolt, Wish, Shadow Ball, Thunderwave.
Make those changes, and this team will be good to go.