@Alopex, I'm pretty sure anyone can auto-cancel because the window of frames from jumping to landing is sufficient to contain the entire arial attack.
Precisely. In regular Brawl, Ganon's shorthop is longer than his Dair, granting the ability to "Lightning Storm," or continuously use the Dair with lagless landings.
Even though Ganon may travel upwards the same height, falling faster after the apex of his jump means that there are fewer frames for him to be in the air, so the arial attack lasts longer than the short hop, creating landing lag.
See, that's my thought, but we don't have the frame data to show exactly how soon, compared to the shorthop, the Dair ends.
It's possible that the Dair ends sufficiently early before the shorthop ends that we can increase the fall speed and Ganon would still have enough shorthop frames to complete the Dair and get the autocancel.
But we don't know that, so it would be good to test it and see. Because then we can increase the fall speed without affecting that "tech".
According to zxeon:
The whole reason Ganon auto-cancels his dair is because you do it on the way up thus it would not be affected.
I think it's obvious though, that the fall speed does also play a role in the execution. The question is, how big a role?
And that's what I wanted paprika to test for us while the NTSC code is still in the works.