yes sure you can but detriovores in there if you add enough live rock there should be lots of places for them to hide. They really don't need any light to thrive,"or the micro fauna that you'd want anyway". I wouldn't add anything that really needed light ,"crabs,shrimpt, little brittle stars etc.,unless you can provide enough light for them to see. There are a couple of places on line that sell collections of these critters. I don't how your sump is plumbed or what your water movement in there is like. I wouldn't put any l.r. in there that had a lot of growth on it either. Because you will be defeating the purpose of adding l.r. to your sump.
hth
chris