honestly it doesnt matter what team you bring.. all you need is your A game.
heres my tip
BUY/Stock up on Hyper potions buy the most you can get. you already mention you buy revives which is good but its already mentioned also your team is under leveled - having a beefy Emboar is useless if you have moves on him like Flame charge - will-o-wisp- flamethrower- and protect..
im trying to point out that I hope you have a moveset that not just all fire type moves.. that hinders you more than you know..
after your battle with any of the Elite 4 I always use my Hyper Potion on who ever needs it and save before the next challenge (just in case)
dont forget to buy choice items in the Battle Subway.. they have vital items for your pkmn to use IN GAME such as a Razor Claw(great for IG) your specs and glasses, you know the hard hitting *hit... all you need to do is get enough BPs for said items..