After finishing the flounces, joined and knit in the round.

I always find it a little confusing to figure out how to read patterns that include bindoffs in the middle of rows. I always have to figure out when the pattern says to cast off a stitch, if you should knit 2 stitches and then cast off the first of them (which is what I’d assume, but isn’t always the case), and then figure out if the stitch you worked in order to do the cast-off should be included in the next count of “knit x”. Sometimes it is, and sometimes it isn’t.

This is what works:

For the hem:
K1, * k2, pass 2nd stitch from the tip of the RH needle over the stitch closest to the tip (cast off one stitch). Repeat from * across, ending k1.

For the flounces:
K1, * K2, pass 2nd stitch from the tip of the RH needle over the stitch closest to the tip (cast off one stitch), K1, pass 2nd stitch from the tip of the RH needle over the stitch closest to the tip (cast off another stitch).
Repeat from * across, ending K1