From the 2008:
210.12 Arc-Fault Circuit-Interrupter Protection.
(B) Dwelling Units. All 120-volt, single phase, 15- and 20-ampere branch circuits supplying outlets installed in dwelling unit family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed arc-fault circuit interrupter, combination-type, installed to provide protection of the branch circuit.
From the definitions:
Outlet. A point on the wiring system at which current is
taken to supply utilization equipment.
This means all pretty much all the lights, ceiling fans, smoke detectors, bath fans, etc. must be AFCI'd.
Bath fans are exempt.
Not always,depends on how they are wired.
Makes no difference.... an outlet is an outlet. We're not talking about receptacles here, we're talking about outlets.
jxofaltrds is right, simply because bathrooms are not listed in 210-12.