Do it with the other button.
Ie if you're going

, then do the Ya Otome input with

and vice versa.
Also the timing is not strict, at all. What you want to do is do the rekka input, let the stick go to neutral for a split sec, THEN do the Ya Otome input. The timing is identical to KOF2k1, if you've played it.
Either the 1st or 2nd hit of the Aoihana can be supercancelled. Its recommended to do the supercancel off

if you can help it as opposed to the

version as the

version won't connect cleanly in the open, while

will.