I would go for something simple
1 lawn mover blenny for algae - smaller alternative is a pictus blenny
Pair of Banggai cardinals
1 firefish
1 yasha goby and pistol shrimp
pair of clownfish
pink streak wrasse
With your rock scape a royal gramma would be very cool as they like to perch upside down under ledges! Gobies and blennies are good choices as always. The tank is large enough for a fairy or flasher wrasse, my lubbocks fairy wrasse is a favorite of mine. A classic clown pair is always nice.
Biota has a captive bred skilletfish or clingfish that is a super cool unique fish!
Also a red waspfish is an amazing oddball fish for that size of tank.