Is this right ?

[Andy]

I will take a shot...

Since you mentioned a HS clinic....I will reference HS rules.

R1 on 3B, R2 on 1B. F1 steps on the pitchers plate with the hands together, so we have an illegal pitch.

Once she has done this, there is no way that she can become legal. Kill the play there and penalize the illegal pitch.

I realize that an illegal pitch is a delayed dead ball by rule, however, I read something that I believe grants some wiggle room

6-2-3, Penalty, note: An illegal pitch shall be called immediately by the plate or base umpire when it becomes illegal. Depending on the infraction, a delayed dead-ball signal may be given.

Since this particular infraction is illegal well before the ball is pitched, why wait to call it and penalize it?

My interpretation only, I'm open to be convinced otherwise.