This sounds like a really interesting run! It should be fun to use the gym leaders field effects against them! I found this out during my first (and so far only) playthrough of reborn about a month ago, where I swept Charlotte with Typhlosion using eruption. because when a move is power 150, STAB, field boosted, flash fire boosted and hitting both opponents, who the hell cares if they resist it!? a variation of this that I just thought of (if someone else wants to try it) is that instead of fighting each leader with their own type, you fight them with the previous leaders type, as if after each leader you are taking their type and using it for yourself.