Sounds like fun!
1. Sure, I can do that. It'd definitely be less annoying than the random evolution.
2. Couldn't give you an estimate on that just yet; I'll probably get on to it after version one of Emerald is done (still got this list to work through before it's ready:
https://github.com/BuffelSaft/pokeemerald/issues; the big issue is all the rematch teams).
3. XY has a limit of 25 level up moves per Pokemon - anything beyond that breaks the move reminder - so there's only so many of those I can include. If you've got suggestions for some of the more interesting/useful ones I can try to add them in though!
4. Yeah that'd probably break a few too many trainers at this point, might be able to get away with giving Pikachu a speed increase at least.
5. IIRC that change was made after I took a break from updating EXWY, so it and a few other ones like Sunflora haven't been brought to this hack yet. They'll definitely be included in the next update!