You can find ro
units on ebay or bulkreefsupply.com. In terms of fish, all looks good witht he exception of the seahorse. They require little to no flow and usually in species only tank because of their specific, and expensive, feeding habits.
In terms of anemones, don't worry about their existance until you decide what you are doing for corals. They are highly light dependant and need pristine waters like small polyp stony corals do.
As for starfish, wait several months until the tank is up and running before considering one. It will help increase success rate some. Bristle and serpeant stars are the only ones I'd even consider keeping due to difficulty level of keeping/specific feeding requirements.