No GFI unless near the shampoo wash basins or other sinks and locations required by Code.
For the record, when I talk of a styling station I am referring to one where ONE stylist at a time uses it. Some salons call a station TWO adjacent chairs, in which case two circuits are a MUST.
Otherwise, a single 20 amp circuit will safely serve ONE stylist. Blow dryers in a salon are short-term loads. Most curling irons are under 200 watts now, so the circuit can safely handle the load. I speak from over 20 years experience in dealing with my brother-in-law's salons.
Now the sit-down dryer chairs are a different story...new ones run around 900-1000 watts each, so no more than two of those can share a circuit. Older chairs may draw more, so if there are many older chairs it would be best to allocate a circuit for each chair. These chairs are usually running for 3/4 to 1 hour continuous at a time.
Bob will fall out of his chair, but the styling stations are very well served using MWBC's, same with the blow-dry chairs. I try to keep any cash registers/computers (a lot of salons have computers for style programs and those programs where a client can see how different styles look on them) and other electronics on dedicated neutrals.