Don't desynch so much in this match up, especially the way you tried to start them by randomly sidestepping (in fact there may have been a moment in that match where you rolled>sidestep desynch *facepalm*). You need to hit Jiggs hard, because against a good Jiggs you won't hit often.
Also don't throw out random dsmashes vs jiggs. You were lucky against this person as he plays a grounded Jiggs so it would pay off, but against a bair spam you're just setting yourself up.
Learn when to punish(/and not to) with shieldgrabs, you got lucky a couple of times because the Jiggs buggered up on spacing, but there were times after getting hit you threw out empty grabs. Instead WDoos (if you can that is, if not LEARN THIS!) and then grab/ whatever.
It's cool that you can start a hand off, I'm not sure if you were spamming them to show that or not, but usually it's best just to smash off the grab (unless you're at the edge ofc then handoff all you want). Jiggs will die hella early if you can get the grab>smash, if you're able to grab Jiggs and she's living till 100% you're doing it wrong. Also when you have the percent BLIZZARD, almost every grab should be accompanied by blizzard and headbutting, not doing so is giving up free damage.
All that said good luck with your ICs dude they look like they have bountiful potential.