1. How would you go about doing them?
2. Also, the bair hit when you fall off of the edge and knock the opponent farther so they have no chance of coming back.
3. Another is the dair from the edge. I try to do it but I keep falling down instead of recovering to the stage again.
4. OT: The Ken Combo....I can't dair or double jump fast enough to catch my opponent like Ken does.
I added in those numbers so my answers will be easier to read.
1. An "edge aerial attack" (commonly called a ledgehopped aerial) is done by pressing down or away from the edge (pressing down will fastfall, pressing away will not), then immediately using your double jump to jump back on the stage. Of course, it's very easy to throw in an aerial attack on your way up.
2. This is pretty easy to do once you have the timing and know how far you can drop. Just drop from the edge (with down or away again. Down gets you there faster, but if you use away, you can float out much furthur horizontally and still recover), then when at the right hieght (which you'll learn with practice), hit back + A + jump all at the same time (acualy, jump should be a split second before A). After the lag, reverse upB into the ledge.
In general, the double jump's height counteracts the lag from the aerial almost perfectly, and the height at which you end up after the aerial will be the same height as when you started it.
3. It's just a ledgehopped dair. Drop from the edge, then hit down + A + jump (jump a teeny bit before A, like before), and DI onto the stage. Easy as that.
4. By Ken combo, you mean the fair/bair to spike, right? This dosn't require you to be fast at all, so I'm not sure what problems you're having. My guess is you aren't tipping the fair. A tipped fair sends your foe straight up, while a non-tipped fair sends out. In general, you can only land the spike after a tipped fair (there are a few exceptions to the rule, for example, Shiek at mid% when you have full forward momentum). There's way more then enough stun time on a tipped fair to double jump and dair without your opponent beeing able to escape it.
I hope that helps ^_^