How is it clear to you that there's a delay to dropping guard when nothing touches you...? I'm pretty sure there's no delay.
I have no idea how long it takes to go from crouching to standing position, but it's not important.
If you want to do 6A, it will work whether you are standing or crouching, so you don't need to care.
Same goes for any double tap, including 11A, 22A, 33A.
If you want to perform a standing 1A or 3A while you are crouching, just forget about it and use another move instead. Again, no reason to care how long it takes, because it takes way too long anyway.
You also should not want to perform neutral attacks after you were crouching for any reason.
If you blocked an attack that forces you to crouch, knowing how long it takes to get back to standing should once again not matter, because you should probably block or sidestep what's coming next since it will beat almost any attack you try to use.
Could you give some examples where you think knowing the rising speed would be beneficial?