>>53731088I've toyed around with the concept of a Kanto / Johto / Sevii game before. My assumption is that you want a stream of new evolutionary lines to capture that's around the same rate as appear in Kanto (that averages out to about 1.5 new lines per route / dungeon).
That leads to Johto having too few new Gen 2 families to keep new monsters on pace with Kanto. My solution was to sprinkle in a selection of Gen 4 monsters (Lucario on R45, Shellos in the ocean, Snover on R44, etc.).
When it comes to the Sevii Islands, my idea was to use Gen 3 Pokemon in it, seeing as that's the generation that the Sevii Islands originated, and the Sevii Islands seem semi-tropical like Hoenn anyways, so it's a happy coincidence. It'd be stuff like Lotad in the water at Bond Bridge, Zangoose and Seviper in Five Isle Meadow, Flygon in Sevault Canyon, etc.
Meanwhile, I'd have some regional variants be available as in-game trade, plus a tiny section of Gen 5+ Pokemon available in the Safari Zone to help fill out each type to at least six non-legendary lines. If you want, I can try to quickly recreate my list, it's been literal years since I compiled it.
