Counter is inconsistent vs blizzard. Blizzard outranges counter so counter can miss. Honestly I don't think FH fair is good vs IC. It's asking to get uaired for days. I find rising SH to be far better.
Shield beaker beats blizzard easily enough though. You end up taking 2% since you sick your hand out but they take more and it separates them surprisingly often.FH dair OoS is really good vs IC imo. They have horrible traction so tipper fair knockback will have them sliding pretty far allowing you to reset to neutral safely enough.
If you've already used your midair jump and are about to land on the stage with no platform to save you, right before you land use dolphin slash. If IC wants to punish your landing they'll have to input grab before you land which means they won't be shielding. So if you wait as long as possible DS can actually end up being a landing option. If you whiff you get grabbed and die, but you were about to get grabbed and die anyway.
If they're recovering low, DB1 is really good. After getting hit, nana will panic upB so that when popo then upB nana won't be synched so they just fall. If you're amazing, you can spike popo out of upB, but it's really hard. Counter > side B recovery.
DB isn't good vs IC unless they hit your shield, while synched, since it's asking to get punished. Other than that, if you're onstage, DB is bad. The mixups get you grabbed, if they shield you get grabbed, etc.
Also, while I admit you should look to top players to see how they play, it's important to recognize which matchups they're likely good at. Mike is a smart player for sure, but he doesn't know the IC matchup as well as kadaj does for example. Before last summer he was horrible vs Diddy until I started teaching him a ton of stuff about the matchup. I love Mike, but there are matchups he doesn't know so dismissing advice since he didn't do it is silly. No, he didn't use SB vs vinnie to beat blizzard, but probably because he didn't think of it- not because it doesn't work (because it does). You should take all the advice you can from people you can trust and then go to training mode and test if it was accurate.