If you are tearing out everything, and it is a guest bath [so I assume modest size] I would suggest lining the entire room with moisture resistant sheetrock. In a small bathroom, it will not be a large additional cost but it could prevent repairs in the future. Especially in Florida!!

I have no humidity here in Phoenix so no need to worry about moisture resistant backings. In fact, it is so dry we don't even need to towel off after getting out of the shower --water just evaporates instantly.:-)