I get the feeling that maybe your tank hasn't cycled yet? Is that what you mean "jumping the gun"?
Your anemone will need to be fed meaty foods, I hope your LFS shared that info. Buy some frozen silverside, thaw small bits and feed the anemone directly.
Your lawnmower blenny might also benefit from food with a higher algae content, if the tank is new, there probably not much grazing for him..