I forgot about the preflowers (thanks for reminding me faithlesxxx). So I've checked them using a 10x loupe and I can see pre-flowers with pistles (white hairs) on four of them - this was the best I was hoping for out of 7 plants.

Can I assume they will stay female as long as I don't stress 'em out anymore, or can they still go hermie? Do hermies have both sex pre-flowers?

Thanks for your help.