for that sized tank you should be fine. one of the biggest mistakes people do in the first 6 months of setting up a tank is overloading it with cleanup crew. they keep buying cleanup crews to combat the startup algaes that occur. then when the algae dies off (due to the tank reaching equilibrium) that all of those cleanup crew critters start starving.
with that sized tank you could easily go with 20 of each to start on the snails. i would not get
bumblebee snails though. Ceriths would be a much better choice. bumblebees are a welk. another predatory snail like Nassarius, just not very aggressive, but can be opportunistic if given the chance.
coral
banded shrimp are very aggressive to eachother. hopefully they will each find an area of the tank to stake out a claim. if not than they will kill eachother for the best spot.
your tank is big enough that if they each have thier own island or area you should be fine, but just do not be surprised if you only end up with 1 or 2.
the sand stars may starve.
such a new tank will not have the infauna population needed to keep that many stars alive. a tank of that size will prolly only be able to support one. any more than that and the DSB will not function properly due to predation of the DSB by the star. Ceriths once again are great at sifting and keeping the detritus and algae down to a minimum on SB.
now get back on those hands.
G~
