Just want to say thanks in advance for comments. This site is incredibly helpful.
I recently purchased a 72gal
FOWLR tank second hand that is completely cycled, with ~25lbs of live rock, and 2 damsels. The sandbed is quite minimal but there are amphipods and copepods living in there. I was happy to see them in there.

I intend this tank to be a docile tank with shrimp & crabs.
I know I need more live rock and can purchase it already cured from the
LFS nearby. The question is do I need to quarantine this cured live rock or can I put it in the tank directly? Also, I could purchase it online and if you think this is better than the
LFS then please list a recommended vendor.
Secondly, I want to add a clean-up crew. Should I do this before or after fish addition? I'm guessing I need to add it after the live rock. What clean up crew do you recommend for a 72gal tank? #'s, species?
Thanks again,
ctmedman