Hello VTaxi,
Volcanion for sure is a heat Pokemon to build around in rain teams, but both Pelipper and Volcanion like partners, which can cover up threats such as Kartana, Rillaboom, and Tapu Bulu. Also it appreciates faster teammates for sure and an Electric-type resists or even an immune to Electric-type STAB attacks. I would recommend something in this direction:
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You can use Tornadus-T over Zapdos, if you prefer breaking power with a Nasty Plot-boost. But this could be an option to try out.
Ferrothorn can cover up Rillaboom, Tapu Bulu, and kartana, and it further helps against Electric-types such as Tapu Koko and Zeraora and it can check Tapu Lele as well. Seismitoad gives that team a great Electric-type resistance, and Pelipper can act as a supportive tool, meanwhile Ferrothorn can set entry hazards with either Stealth Rocks or Spikes. I feel this or a similar structure can help you a lot for laddering purposes.
Hope that helped :)