Try Olimar. I play a lot of Oli, and ICs have never seemed that difficult.
-Fsmash desynchs them. If you Fsmash everytime they approach, even if they shield then they will not be able to grab combo you.
-OverB can't outrange Oli's grab, so as long as you don't pummel you shouldn't get punished for grabbing (though I would suggest avoiding them anyway).
-Usmash will usually hit the rear climber, so after about four Usmash exchanges (meaning you will be Dsmashed or grabbed), the rear climber will be on the verge of death and it shouldn't be too hard to finish from there. Usmash also pushes them too far back to shield grab, and Oli has so little cooldown that he can Fsmash or just move before getting hit with any attack.
-Oli's overB stops the ice blocks dead, usually canceling three to five of them before the pikmin dies.
-Anytime the climbers are above you, a simple Uair will seperate damage, and usually lead into a follow up Uair or two against the rear climber.
-Fair takes ICs out of Squall Hammer (I'm not 100% sure if it does when they are grounded, but it most definitely does while they are airborn).
-If the ICs do get off a grab combo and try to spike you, you can upB meteor cancel the ledge as you soar past. Only characters with tether moves can 'meteor cancel' in Brawl. Oli can do this successfully as high as about 120% (beyond that I'm not sure if the rear climber's spike is too strong to keep this from working).
You're welcome to disagree. I'm just sharing my experiences with Olimar.