Accept that even though the cleaner shrimp is established any 'predatory' type fish you add may eventually decide its lunch. Same with many of your smaller fish.

A couple possible reccomendations I have:

Hawkfish - longnose, lyretail or flame (these are shrimp eating machines but well behaved with similar sized fish).

Basslets - many of the Carribean basslets are hardy but can get largish (6" +) and many are semi piscivorous like the harlequin and tobacco bass. Also if you decide to forgo some of the smaller fish Hamlets are great reef safe predators that would do well in a 55 - 75 gallon.

Dusky Jawfish - not as cute as goldhead or bluespots but definitely a micro predator. Again not safe with small shrimp but they will grow on you.

If you have the cash / space maybe one of the dwarf morays like the ghost eel or if you have deep pockets a golden dwarf moray are fascinating predators that do well in 30 gal + tanks. Given your current stocking levels I'd hold off on anything until your new tank is up and settled in before adding anything. I actually would take a couple fish out before adding any type of micro predator.