If you use Plasma Whip, space it so that it hits in front of them. If you space to try to hit them, there's the risk you dead spot it and it ends up poorly for you. But if you try to put it in the range they are committed to dash and can't shield, everyone will run into it. If you EVER see an IC dash dance repeatedly, it means they are going for a ******** desync option and you should just immediately throw out Side Special into it on reaction.
If you dsmash, do it only once if you aren't sure it will hit. I try to cover it with Flip Jump for the most part since it's safe on shield unless you commit to something else and Flip Jump has invincibility frame 1. The goal isn't to use Dsmash to do a bunch of damage, but to use it to get underneath the ICs. Then you Uair them all day.
If you end up Dsmashing one for sure, just keep throwing out Dsmash over and over. Like in doubles, people will run into Dsmash trying to save the other climber.
Use your mobility to bait ICs into overcommitting on Uair. Get under them. When juggling separation, it's better to Bair Nana away so that you can try to engage Sopo without interference. Once you hit Sopo away again, you should THEN go back to going for Nana. A lot of people get grabbed because they focus too much on Nana and forget to worry about returning Sopo.