Do bathroom lights have to be GFCI?
Keeping this in view, what has to be GFCI protected in bathroom?
Per 210.8, you must install GFCI protection for all 15A and 20A, 125V receptacles located in bathrooms, rooftops, and kitchens in commercial/industrial facilities. However, GFCI protection is not required for receptacles installed outside a commercial or industrial occupancy.
Also, do bathroom lights need to be on their own circuit?
Bathroom-circuit receptacles. It does not require a separate circuit for each bathroom. One circuit may supply multiple bathrooms as long as only bathroom receptacles are supplied. Lighting outlets or receptacle outlets in other rooms may not be supplied by this circuit.
If your lightbulbs will be outdoors and you do want to protect them from ground faults, then the wire to the switch box (both line and neutral) should come from the Load side of the GFCI, rather than directly from the panel (or the GFCI's Line side).