Here's what I'd suggest:
A few small hermit crabs, redleg maybe
Some nassarius snails (they burrow and clean sand, as well as scavenging)
Some random algae snails (turbo, margarita, star, etc)
Maybe a tuxedo sea urchin
And whatever harmless critters turn up.
Why don't you want shrimp, may I ask? Some of them are pretty shy, if you just don't like the look. You'd probably never see a peppermint except for a few glimpses.