Yep, this was me when I first started out. The chooser was cool but didn't really answer the question of which one I should use first.
I eventually settled on Mint. Cinnamon left a lot to be desired imo, but otherwise it worked quite well and I'd recommend it as a first distro.
I've been kind of mixed about this myself.
Keeping certain mechanics to certain games (and their subsequent rereleases/remakes) make those games more unique in their own ways. And then, of course, there's the pandering in the live service spinoffs like GO.
But at the same time... yeah, I'd like to see certain mechanics come back. I don't miss Seals (or Contests, really), but I wouldn't be against Megas making a surprise return someday.
I don't mind Mythical distributions being mostly online nowadays, but I would love to see the in-game story events that you had to go through make a return.
For all of its flaws, I think BDSP did that quite well.
Happiny's in, no worries there.
Are you trying to keep it to the regional Pokedex, or are you okay with transfer-only Pokemon like regional forms?