Stop rolling. You're freakin' IC's. They have the second best wavedash in the game. Use it.
You need to jump out and rescue that Nana when she's only a single jump's distance away from the stage. Just jump out and forward-B. It's more difficult to edgeguard than you might think.
Try to learn to button mash faster with the squall hammer. I'm not sure if that's a skill that a person can improve, so if you can't, I guess you'll have to live with that handicap.
You had many grabs with Nana right there that were not excecuted well. Either learn to chainthrow or learn to Wobble. It will improve your IC's game drastically.
You seem to have a slow reaction time which forced you to keep your shield up longer than necessary. Unfortunately, there's not much you can do here. I sympathize with you because I have an atrocious reaction time (much worse than yours), and I have yet to find a way to improve it. To compensate, you have to learn to read your opponent's better. That way you can react to your opponet's moves before he/'she executes them. The only way you can learn to predict effectively, unfortunately, is with practice. Play more games and the mindgames will come.
Sorry if any of that sounded demeaning/condescending. I'm not too good at providing constructive criticism without offending people