I would wash before & if you wash one fabric, I would wash all. I would do like hues and colors together, so all the dark greens, then the light greens, etc. If you get a bleeder, you will have to either figure out which one it is (wipe damp fabric on a piece of muslin to see if the color transfers) and treat that one fabric or just treat the whole batch with Retayne.
Lovely fabric selections!