So I was doing some training with DIing out of waveshines yesterday and noticed I've been doing it wrong this whole time. I was just smashing away and a little up when I was expecting to get shined because of the way you fall when hit in air, but I thought I remembered something about a different ground trajectory so I googled it and it looks like the best DI is straight up (or quartercircle from out to up if you're fast enough) to get out of a grounded waveshine (If anyone can confirm this it would be nice). I was sometimes able to jab the 20XX robot out of its wavedash with DI up>immediate jab. From here it's safest to dash away I think because a human Fox will most likely react to jab with hold down to CC a second jab and attempt to either grab, waveshine upsmash, upsmash, or fsmash. If you get shined off the edge of a platform to the stage below the best DI I think is instead straight down to get to ground fast enough to shield a following aerial. The same DI should be used to grab edge if a grounded shine is going to push you off the stage (don't forget to let go of down in time to grab edge).
Speaking of the edge, I don't see anyone using Link's invincible DJ stall and I see very few people that are consistently getting off the edge frame perfectly. This is understandable of transitioning players or dual mains but Link is able to let go of the edge about 4 frames sooner than every other character (except maybe YL but I don't think even YL has the fast cliffcatch animation). If you get this timing down Link's perfect ledgedash (without ECB manipulation) has 9 frames of actionable invincibility. This is enough time for the hitboxes of upB (8), dsmash (9), dash attack (1 frame dash +7), utilt (9), and jab (6) to come out. Dsmash, utilt, and turnaround upB are probably the most useful moves but require frame perfect timing to execute. You can also throw a bomb forward (7), backward (7), down(6), or dashing (1+8). A less difficult option is ledgedash>roll in. This gives 5 frames of leniency on the ledgedash (assuming you buffer the roll during the ledgedash) and will remain invincible through frame 19 of the 37 frame roll. You'll probably get hit again but this option makes your opponent have to work to get you offstage again. Spotdodge dsmash or utilt can be used as a bait but is otherwise strictly worse than the frame perfect moves without spotdodge. Aerial bomb tosses (6, all directions) can also be done invincibly directly out of your ledge jump if you happen to have one in hand.
Last tidbit that I think I haven't actually seen anyone doing is using what I've taken to calling bomb DI. Basically it's a last resort for escaping techchases by displacing yourself unexpectedly. It's performed by Z-dropping a bomb just before you land and smash DIing in the direction you want to go. It's especially useful for getting out of platform techchases when you don't have a jump. It's more useful at higher percents where the bomb will send you further. I escaped Marth's tipper fsmash off the side platform of Battlefield without a jump the other day with it and because that move is so laggy I was able to take center stage off it.
On a side note, did anything ever come of this? Been getting a better feel of when I'll sweetspot lately but that info would be nice to have. I know it's really complex though. Also thanks for the projectile frame data, bomb toss data is