i appologize if i came off rude but heres a few things. trying something to "try it" isnt really a successful attitude. im by no means a tree hugger but my hobby is fish and when fish, corals, inverts of the sort are being over harvested for peoples enjoyment it doesnt take much to get restrictions on the species we keep and their availability.
as for your CC star not eating the shrimp it may just be an exception, every animal will have its own personality or it just may be a matter of time.
live rock acts as a main factor of your natural filtration, along with flow, sand, water changes at the very basic and sumps, protein skimmers, carbon/phos reactors to be even more benificial. an anemone will most likely move through most of your tank until it finds a spot it likes. this is usually vary between all nems as some prefer more flow then others and more light. ill say every one has there own personality. the reason i asked for your water parameters is because anemones need reef setups and conditions and the reason i asked about your lights is because you doubted yourself saying "i believe they are t5" so i was double checking. power compacts still qualify as reef lighting but i would rather see an anemone under t5s and better yet metal halides. again im sorry if you took what i said the wrong way but these are things to consider and have a heads up before making a purchase regardless of price. your also going to want to realize if an anemone dies it will "nuke" your tank, killing everything inside. this is where when it gets up and walks becomes a big issue because finding its way to a power head will just result in a blended dead one so thats another thing to consider. ultimately your going to be the one who decides if you get the anemone or not, i just inputted my 2 cents as everyone (which includes you) is entitled to their own opinion.