Sorry but the Infernape set just doesn't make any sense at all. You're using Choice Band...with almost minimal attack investment, and only Mach Punch and Stone Edge as physical moves! Fire Blast and Grass Knot are also both absurdly weak without Life Orb. There are just so so many pokemon which would completely wall this, which is definitely not the point of a frail mixed wallbreaker like Infernape.
Apart from that, you have a major stall weakness even with Forretress, due to having no Rapid Spinner while opposing Skarm / Forretress set up completely for free on Jirachi / Cresselia / Swampert.
Gyarados is another major threat. Sets up pretty much whenever it wants on your team, can take out SpDef Zapdos easily after a small amount of residual damage, and goes straight through the rest of your team, including Swampert if the Gyara carries Taunt (which most do).
LO Starmie again, really should 6-0 you if played competently. Cressy / Jirachi / Zapdos can take one hit assuming they manage to come in safely, but after that you've got no way to outspeed it and nothing which isn't 2HKO'd.
Just some quick fixes, run the standard Stealth Rock set on Swampert. You get much more out of that than from Toxic (since nearly all of the things which like to come in on Swampert, such as Grass types with Natural Cure, Skarm + Forry etc, don't care much about it). This frees up Forretress to use its standard Rapid Spin / Spikes / Toxic Spikes / Payback set.
Infernape, definitely definitely change to a standard set with Life Orb. I'd recommend staying away from Nasty Plot / Swords Dance and running a physically based MixApe with U-turn to abuse your entry hazards. Check out the analysis on-site anyhow.
You need to change your Cresselia. In particular its moveset leaves it completely walled by Dark or Steel types, which are both very common. I really can't see that set sweeping against a well made team, ever. Plus, Moonlight is pretty poor in OU with Tyranitar on 20% of teams. I'd suggest trying a bulky Calm Mind Celebi in its place, covering your issues with Water types to a large extent, while keeping the same general role as Cressy.
Last thing, use a Choice Scarf Rotom-W over Zapdos. You really really need a spinblocker with a pretty bulky team reliant on entry hazards. It's also incredibly important on this team to add something with some speed to revenge kill Infernape / Starmie etc.
If you go with these changes I can guarantee they will help the team a lot. Try them out, if you have any more problems then be sure to update back here. Good luck :)