Herbivorious crabs are fine with jawfish. All the common clean-up critters should be able to coexist with the fish.
What else is solely up to you What kinda fish do you like? For a 54 gallon, 2 or 3 more fish would round out the population very nicely IMO. I'd consider flasher wrasses (one male and 2 females) if your tank top/canopy is covered/sealed. But again, it's solely up to you what you like. Good thing is most fish will get along with jawfish.
I learned from my 55 gal corner bow front that any fish that needs a lot of swimming room is not a good choice. We had a fairly large damsel and he was always getting scratched while racing around the back of the tank. Everything is a little tight in the back corner.
Here is the list I am planning on:
3 Carpenter Flasher wrasses
1 Fire Goby
1 Crowned Pearlyscale Butterfly
1 Longnose Hawkfish
1 Flame Angelfish (maybe)
1 Green Mandarinfish (After a couple of years to get the tank's pod pop established.)
So far I have a 4" DSB and 60 lbs of live rock and a Brittle Star (non green)
The Jawfish (Sadam) was constantly being bombed by my Cinimon Clown.
The clown would pick up pieces of crushed coral and swim over top of his hole and drop them, covering his entire home. Eventually the Jawfish died.
That was the only fish I lost in three years.
Is it reef or FO. I have a 90 gal FO with CC .I am doing a big change in it.The CC collects to much crap.I have had it for about the same 7-8 years. I have a real hard time with Angels