Batting 10 in FP

[Ol Blue]

NFHS covers this with 2-57 Art 2 a and b.
A pitch had been thrown to the next batter B1 who is now on first and B2 is in the box before a pitch thrown.
3-4 Art 2 c penalty says if discovered after pitch to next batter Play stands. if illegal sub on base she is called out and restricted to bench.
FED I would inforce Illegal sub as by rule this takes precedence over BOO (3.4 art 2b penalty) Remove R1 the FLEX from second call her out and restrict to bench, leave runner on first and have B2 step in and bat. I don't know if that is exactly right but thats what I would do. I don't have to worry about it for awhile because we play HS softball in the fall here in Ga.