Well, there are several answers here. Benzoate is too weak to stabilize gelatin against bug attacks except at high concentrations so I don't use it. It was used in the old color stabilizers but it made the film or paper tacky to the touch at the concentrations needed. Sorbitol does the same thing, rendering things tacky. Thymol is not a notable oxidant or reductant AFAIK.

You need a stabilizer (Bacteriostat) that works against gram negative and gram positive bacteria and also against molds and fungi. This can take 3 chemicals to do the job properly. And, the bacteriostat must not hurt the photographic process.

PE