Ok guys, I have some info for you all.
I couldn't remember if you guys were doing the b-air from a short hop or a normal one, so I tested it out in training mode. Just to let you know, in my version, it's impossible to jump out of a short hopped b-air. In my version, I checked, and the animation of the attack doesn't end until after you land on the ground (I zoomed up close and was testing to see if you have a landing lag animation, and it does). Now, if you're talking about L-Cancelling the first one and then double jumping backwards to the opponent, I can see that happening, but you can't short hop b-air and then jump out of it to another one, or any aerial attack, unless you're jumping off of something so you have more air time than usual. I have the last version of the game, so they might've made the attack have a longer animation, but I doubt it.
Oh yeah, I'm gonna share some tricks with you...
Using the neutral or b-air on an opponent in the air (higher than short hop height) allows you to advantage WD (WD coming from the air) and you can get some crazy distance (as with any advantage WD), but it allows you to keep a juggle going for a lot longer by sliding on the ground towards the opponent who's still in the air.
Here's another trick for those of you like me who can't WaveDance. Instead of WaveDancing, I've found something almost exactly the same in effect. It mixes DashDancing and WaveDancing together, so you dash and WD back repeatedly. I think it's faster than WaveDancing and gives you almost as many choices.
I've been playing training mode only for a while, cuz my brother doesn't like to play too often, and I've just been working on coordinating my attacks and multi-tasking, if you will. Doing things like attacking to WDing, catching a bomb and WDing when I land, etc.
There were a lot of things I wasn't so good at when those vids were made (don't think I ever posted the link in here, so here it is:
http://garde.codetime.com/ssbm/ , Kenshin, you better post something about them!). I've mostly fixed my L-Cancelling problems that were there, and I'm slowly learning how to WD instead of roll, because WDing is harder to punish in most cases. And I've learned to NOT jump into Roy or Marth's f-smash, that's a no-no. I'm pretty sure those two are the only ones that have an attack used regularly that covers a fair range in front and above them, although I'm thinking Falcon's and Samus's up-tilt might be similar, although they're not really used too often, in my experiences (mainly edge guarding moves). I don't d-air as much, and I use a lot more of my aerial moves, and I'm even learning how to time them so that they finish before I land so I can advantage WD from them to keep my opponent in the air more effectively.
Kenshin, good luck with Guide ver. 2, are you gonna be starting a new thread or keeping it in the old one? Oh yeah, not posting is completely understandable, you were busy, but I WAS wondering where you had been....