More in depth, you will be rolling/poking/running/dodging/jumping away a lot. Your goal is to separate the 2 and you have the range and the shield push/autocanceling options to do it. As mentioned, you actually can grab them as long as you throw a pummel immediately to interrupt whatever the other climber may do to interrupt you. Back/forward throw exclusively, back throw if you stunned the second climber with a pummel so that your act of throwing the main one away causes the second climber to walk after them, then immediately fsmash the ever living flying dog **** out of it. Theyre light, an fsmash anywhere over 16 will flat out kill a climber on most stages, anything over 25 is guaranteed. If you do this, you're now ike versus a single climber, and if you manage to lose this matchup then chances are you're pretty much a lost cause. You have range on them, you can zone them rather well, and their projectile game is laughable as it carries along the floor or is close range, and their goal is to get their mitts on you anyway. Retreat fairs, nairs, bairs, and box a lot.
As for stages, you want slants, walls, platforms. Anything to disrupt the flow of grabs should they get one off. You're looking at yoshi's and lylat for neutral options with battlefield being a distant third. For counters you have pokemon stadium, delfino, brinstar, castle siege, and a few others. Play the stage and a lot of keepaway if you need to but being able to tech a spike is big.