Teammates should not be able to edgehog eachother. Rather, teammates should be able to grab the legs of their dangling friends. This'd make getting up for both a bit difficult (except with the magic of edgehop) but could be used to help teammates who just wouldn't quite reach it otherwise.
Weight limits would be a bad idea. It'd be unfair and cause a lot of whining.
Being able to do it on enemies wouldn't make sense, as why would they let you? Plus it'd eleminate edgehogging.
The Ice Climbers is something I hadn't thought of. Since they're on a team even when alone, this would also affect tournament play. It could be a way to help Nana make it, or to keep her with you when recovering. It'd also get rid of one of the most annoying circumstances: Getting edgehogged by Nana.
This could get interesting in 1v3 battles, double Ice Climbers teams, or (hopefully) 4v4 battles.
:::
When you latch on to your buddy, you'll get some invincibility frames while your partner does not. If you're hit and he's not, you'll fly off as normal. If you're both hit, you'll both fly off as normal.
If he's hit and you're not, he'll fly off with you still attatched. While together, you'd fall at 2/3 your combined falling speed and acceleration. The top person could still act normally, but this new gravityy would affect his jump, and (with FF on) he'd be able to perform few attacks without hurting you. You'd continue to act as if on the edge. You'd go prone when you reach ground. If he makes it up but you're still below edge level, you'd let go and grab the edge.
On the edge, the saver would be able to drop (and enter the above mode) or normally (not jumping, dodging, or attackuing) climb up, pulling you on, too. Climbing would be slower than normal, the exact speed determined by weight of dangler.
The lower person could drop (funtioning normally) or normally climb over the top person, the time taken determined by size of the top person. If he's knocked off while you're climbing up (or if you climb up after he's knocked off) you'd continue the climb, and perform your ground-jump off his head when you reach the top.