I'm happy to answer those!! The extra options with Leaf are a bit of a tease. In every other event, I hide them, but in that initial Leaf event I wanted to give you an idea of what you could & couldn't pull off.
Scenes are tied to evolution! Its why the 2-stage mons you get access to at the end of the demo have more than either starter - they evolve less, so they have a greater share of the total scene pool for that evo line, if that makes sense.
The grinding in this game will come from obtaining the special monsters. Once you have them, I'm not going to require you to do anything except evolve 'em to see their full suite of scenes.
I appreciate your kind words about the Innates! I really enjoyed making those sets, so I'm glad they were a standout to you.