Cabbage spaceman.

You should be harvesting the greens in time for the others to heart up

There's no reason why you can't grow any cabbage as greens - it's traditional to do spring greens because there's not much else around then.  You need to cut the ones you'll be getting rid of as soon as they start to touch the plants on either side, and the hearting plants will never know they were there.  Just keep everything well watered and fed.