You should never drop engineers.
4 Engineers are not enough for USN, you need 5 or 6.
Restorers are usless.
Seamen is not needed for Monty or Nebraska, the spread is fine without them and they don't boost enough to be worth it on a BB.
Minimal 4 Repairs with 130+ Vets are needed to Repair Cap.
Ideal crew is 6 Engineers, 4 Reps, scout, BO, 2 Acc Gunners and 2 Rld Gunners if you want AA or HH. (When running AA or HH, run 5 Engineers, 3 Reps + scout on Nebby or 4/3 on Montana with AA/HH)