I need suggestions, please.

[FishyFishy!]

I would probably do one hermit (but something nice like a Halloween), one snail, and the peppermint. I wouldn't see much of a point with the emerald.

If you want a crab, I would suggest maybe a porcelain crab. They are far more lively, and their diet is more filter feeder style. Emeralds would probably die off quickly in a small tank like that.

As for the chromis, they definitely are not a nano fish. They prefer to be in groups, and are also very active swimmers. I would stick to a small clownfish or a clown goby.

Jawfish are not nano fish either. They probably need at least 20-30 gallons.

With the deep sand bed, You could get away with a pistol shrimp and goby pair.

In a tank this small.. I would stick to one fish max.