Your default position in this match up should be on a platform. You can't get grabbed on a platform or in the air without the icies doing a very telegraphed slow jump approach. When the icies do jump, use your aerial superiority to separate them.
If you ever get grabbed, mash as hard as possible. Icie grab punishes are very good. If they start wobbling, there are all sorts of stupid tricks such as stare at them irl or make noises off beat to mess them up, but if they're good, these won't work anyway. Focus on not getting flustered. If you get mad, you're just going to get grabbed again.
Utilt rest is very good on both sopo and nana. Same with shfll uair to utilt to rest. Nana is usually really easy to rest, and unless you're at like 70% + where you will die to the punish, it's usually worth it.
Most icies are dumb and spam grab. This is really easy to bait by floating near them when shielding, then jumping out of the way right before you would be in grab range. If they do a dumb shield grab, you then float in and hit them with an airial. If you keep that up, nana will eventually get separated because she never di's. Another thing to do if you get a read on their shield grabs is to go in with an autocancled nair so you land right in front of them and then mash rest. When they try to grab you, your rest comes out and they die.
Edgeguarding is fairly simple. When it's sopo, unless he can reach the edge with his double jump + upb, he has to use side b. You can cover all of its options by waiting on stage. Forward or down smash if he tries to go to ledge, and follow him if he goes on stage and hit him with rest / smash attack / ariel. If he goes low, you know he has to grab ledge, so just grab ledge and roll. If it's two climbers, the up b has very strange hitboxes. Get some practice against it so you know where it hits. The plus is that nana is usually a free kill if they ever use this move. If the climbers side b together to recover, its really easy to hit them out of it with an airial, which usually separates them. Then go kill nana, then sopo.