Haha, no problem man.
If you're referring to the "usual timing" as in the usual timing for jab canceling, then yeah; the timing for tilting "back" and hitting "down" are the same. You can even just tilt back as you jab so that you buffer the turn and then BAir a little bit before to take full advantage of the 10 frame buffer system (which is what Rykoshet does).
As for hitting short characters with BAir, I'm pretty sure that it's just the timing; ideally, you should try to always BAir so that you can auto-cancel it from a short-hop. This will also give you the lowest possible BAir if you use it on the way up; obviously, if you use it on the way down you can get a much lower BAir.
The best (and most basic) jab cancel combo to use is jab1 -> jab1. It's one of Ike's only true combos, it adds just a bit of extra damage, it refreshes your other stuff, and it also lets you see how your opponent DIs. I personally do jab -> jab combo most of the time, since you're pretty much guaranteed about 17% worth of damage. Another popular one is jab1 -> jab2 -> jab combo; that does about 21% or so (as much as Snake's double FTilt), but it's not as reliable as jab1 -> jab1. The next useful one is jab1 -> dash grab; note, however, that this is not registered as a combo and your opponent can get out of it with proper DI. There's also jab1 -> UTilt/DSmash (good for getting vertical KOs, but UTilt is more common) and jab1 -> BAir (but you know that one already). At the edge, you can also try jab1 -> DTilt spike, but it's easy to see coming. You should also note that the jab combos I suggested are listed in approximately how "guaranteed" they are in terms of frame data; thus, jab1 -> jab1 is the one that is most reliable and jab1 -> DTilt is the least reliable.