Do they still sell the Whole Earth Catolog?
My thought is that it's a drying, or dry storage situation, opposite of your OP statement. Yes, it will be GFCI - required! Low level lighting, CFP, or even LED, would be best here.
The area has either a constant stable enviroment or its maintained to be one.
If they are going to insulate the walls and ceiling, this will change the aveage
room tempertatures, Frankly any new I-valve will change the average room temp. I'm guessing 50 to 55 deg's, 50 to 60 degrees but it also get into what they are trying to store!
If it's always dry (not subject to outside enviroment factors), walls or floors not weaping the owner is way better off. Isolation from house services also helps even a blade wall or enclosing heater, water heater, can make a big difference.
A good portable dehumifilier if the area is good and stable, and they state the working Sq/Ft. of the dehumidifier. (Good for I'm thinking of up to a two car garage-area)
If larger there going to have to have to flip a coin for getting some mechanical involved.
Hope this helps.