mistakingly planted in soil, any way to make this better?

I recommend replacing coco with sphagnum peat moss. It's more acidic, but does almost the same thing as coco. To answer your question: Yes, you can definitely do something to fix potential compacting of soil. Take a tarp, or a big bin, and mix one part coco and one part perlite together. One part being the same amount for each. I have a 7.5 gallon pot that i use for quick measuring because i like to make a lot of soil at once. Anyway, after you mix those two ingredients together, you'll need to add the same amount of either worm castings/compost/natural soil/etc., and mix that in as well. Now that you have your new medium mixed up, you can re-pot/up-pot your plants. If you wait until the medium that the plants are in is fairly dry, you might be able to safely shake and knock off a decent amount of soil from the root ball. Once you have your root ball free of unwanted soil, just pop it in the new pot with fresh medium, water, and she'll be good to go. Cannabis plants aren't nearly as fragile as people make them out to be. I've done re-pots like this multiple times, for multiple reasons. Never once have i had a plant die because of this sort of treatment. Good Luck!