First of all, since u are using Pelipper as a rain setter and defogger, spamming Spikes and Stealth rock from Ferrothorn is a counterproductive static imo. Plz do note that defog not only cleans out those entry hazards from ur side of field but also foe's.
2nd, using rain as a method of reducing incoming fire moves towards ferro is a nice way to increase its survivability, but how often can u allow ur rain setter switch into stealth rock? Without roost/leftover (recovery options only pelipper can access to), ur pelipper cant switch that much into stealth rock for defogging or stall out foe's tank pokemon (seeing a toxic there). Hurricane is nice move (Stab +100 acc in rain), i do prefer scald over hurricane, but again the burning chance and toxic is too hard to pick from. Im not saying using toxic is bad idea (good versus pokemons that like to burn themselves aka conk), but in terms for defogging/rain setting purposes, toxic doesnt seem fitting in.
3rd, ur Ferrothorn has Gyro Ball, and we know that the lower SPEED (sry if im using Spe in short for SPEED) the pokemon has, the more damage Gyro Ball will be dealing. SO plz make sure its Spe IV is 0 !!! U may switch Gyro Ball into Power Whip, still stab for ferro, and mostly will smack them out of field with 1 or 2 whips, but still beware of scald that may burn ferro.