I'd actually prefer Alolan forms over Megas for them, not gonna lie. It would be REALLY cool to see their lines get Pokémon with COMPLETELY different types. Maybe even a new backwards type triangle, like steel, fairy, fighting. You could have a fairy Chikorita that's super effective against a fighting type Cyndaquil who's super effective against a steel type Totodile
the typings fit too! I could easily see feraligatr having a more metallic coat with razor teeth, Meganium getting flowers and a smidgen of pixie dust and half of our fire starters are fighters or wrestlers anyways, shouldn't be a stretch to just drop the fire part altogether and tack on some boxing gloves.