Can I add USB outlets to bath/hall lighting circuit box (not GFCI)?
No, Class 2 power outlets (such as USB receptacles) are not required to have GFCI protection

This can be drawn from the fact that the GFCI requirements in NEC 210.8(A) are specifically restricted to 125V, 15 and 20A receptacles:


  (A) Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in
  210.8(A)(1) through (10) shall have ground-fault circuit-interrupter protection for personnel.
  
  (1) Bathrooms


and is further justified by the definition of Class 2 circuit in 725.2 already taking shock hazards into account:


  Class 2 Circuit. The portion of the wiring system between the
  load side of a Class 2 power source and the connected equip‐
  ment. Due to its power limitations, a Class 2 circuit considers
  safety from a fire initiation standpoint and provides acceptable
  protection from electric shock.


(See also the fact that 210.8 is not referenced in NEC 725.3.)