I think the white one is a roo - I'm not sure on the dark one.
Your white one has what looks like a pea comb and there is too much pink in that comb for a 7-8 week old pullet. The comb on the dark one looks a bit large for its age, which makes me think cockerel, but... it might still be a pullet (I don't see any wattles yet). Wait a couple more weeks on that one.