Update - I have new roots! I think they are coming back.
The problem is, I have 2 short plants and 2 tall. My options are to separate and raise the buckets of the short plants... or can I merely put them back under veg to do a 2nd grow phase after the talls are done?

My other issue is that after 2 weeks in flower, I'm not seeing flowers. Just female preflowers. The talls are still in stretch mode. Do the flowers not really appear till they're done with their stretch?