So I've been messing around with ways Corrin can punish the 2-frame ledgesnap window, and i've found she has some interesting options at her disposal, some more straightforward while others require insane precision. I haven't tested every single move though, I sadly don't have enough time cuz of midterms. All my tests were done on a CPU Sheik in training mode, set on Stop and 85%. Front hit of dsmash at the edge of FD sends Sheik at a low enough angle where she'll have to up-b to recover from a fair distance away, making it easier to hit the snap without the timing changing too much.
First up, hitting the snap with nair is braindead easy; dropzone nair, rising nair, no need to space or time cuz of how big and long the move is. Very low reward though.
Fair and bair require some timing but are still fairly easy to connect. Bair can stage spike if they miss the tech, and fair sends them high like nair does.
I've found that the DFS bite is a good option to punish the ledge snap, specially due to how the charge stalls. Even if it might not stage spike, it still does damn good damage and can kill across the stage at higher percents. In Sheik's case, I've had most success landing the move by releasing the bite just a bit after the first explosion sound effect. Also this might have been mentioned already but after using DFS once in the air, the next bite won't stall at all, regardless of whether you charged the first bite or not.
Now on to DL.
It's probably the move with the most reward as a potential ledgesnap punish (great angle, power and damage) but, in my experience, the hardest to time. I've also only tested aerial DL, I'm not sure if Instant Pin hits low enough to catch the snap. After some testing on Omega Coliseum with the CPU Sheik set at 85%, I managed to hit the 2-frame window with the most success by standing in the 2nd square (about 2 character lengths) by the edge of the stage, jumping as Sheik is in Vanish startup and using Side-b just a bit after Sheik disappears. Everytime I successfully connected side-b, I was pinned right near the ledge, with the tip of the lance passing through the stage.
I also went through the trouble of testing full hop dair, and the results...are quite interesting. Although it's important to note that this move in particular should be tested with another player, because it might just as well not work on a human player with any shred of reaction time and DI. Connecting the dair was actually easier than i expected, and even one hit sometimes meteored (as in played the meteor sound effect) at higher percents. When buffering jump right after, I was able to consistently footstool Sheik, whether she jumped herself or not. If you miss the footstool, trying to recover back normally can drag the opponent with you, potentially stage-spiking them with up-b, otherwise doing decent damage (+10% with some hits of dair and up-b). However, some quick tests on Mario showed that he could up-b while Corrin was still in dair lag (?? i think so, at least) but it was still possible for her to recover. So i have some doubts as to how practical this setup is, that's why it'd be cool if some other people could test it as well.
Amusingly enough, with this same setup, dair > (jump) dair appears to be possible (shows up as true in training mode) but might be inconsistent and will of course kill. Good for style points.
