When it says a number instead of a move name it's because it's a special move, and because certain special moves change and some stay the same under certain circumstances, they give it a numerical value since it wouldn't work to give it a universal name that applies to all of the characters.
The numbers next to your current action refer to how many frames you have been doing it for, this number sometimes jumps ahead or goes into decimal during landing animation and some special moves because of varying rates and lag reduction moves, ie. L-cancelling.
As for measuring recovery capabilities, pressing R + D-pad Down enough times will bring up three dimensional star shaped markers around the stage and in the air, you can use them to compare distances to a more accurate degree. And if your talking about when you're spinning through the air uncontrolably after being hit, you can break out of that the same way you break out of grabs, there is no set time. And as for reaching maximum jump, I don't get what you mean, judging from what you're asking, I'd say just jump and wait until you stop going up.
As for the attacking during another action but not being able to do certain other things, well, during certain frames of some moves you are able to do some things but not others, like when you hit the ground, you can shield on the first frame, move/jump/attack by around the 4th frame for most characters, but the whole landing animation takes much longer if you wait. Also, during certain attacks, you can repeat it before the animation ends but can't do anything else, like with most weak attacks, or Marth/Roy's ->B.
