oh hey reading through the thread I saw you had been out of touch on pokemon for a long time, I know a handful of game mechanics I can run by you in case you aren't aware of them due to the massive changes from gen 2 to gen 8. I doubt you'll be able to impliment all of them, and some of them are not too popular as well but it'd help as a reference.
1: Since gen 6, the move hidden power always has a base power of 60. Likewise, since gen 4 there are NPCs who tell you what type a pokemon's hidden power happens to be. Given how important hidden power can be to a moveset I would reccomend having a readilly handy way to check hiddenpower, either as a feature on the summery screen or a hidden power checker in every pokemon center.
2: Breeding mechanics are very user friendly as of gen 6 and 7, but in gen 8 even novice can get very good pokemon. This is because the hidden abilities (a mechanic from gen 5) can be passed on regardless of gender now. A cool feature introduced in Gen 6 is that parents' pokeballs can be passed onto the infant.
3: Related to breeding but its deserving of its own spot; egg moves can be passed on from both parents now.
4: as of gen 6, when a pokemon evolves, it can learn a move directly from evolving, regardless of what level it is. Many moves often gained via level up as a result of evolving at the right level (Wing Attack is learned traditionally at level 36 when Charizard evolves from Charmeleon at that exact moment for example) have been made as such evolution moves (as suc in this instance Charizard can learn Wing Attack at any time regardless of level when Charmeleon evolves)
5: In gen 6, an item called an ability capsule was added which can change the abilities of pokemon when consumed if they have more than one standard ability (Rattata with Guts can get Run Away and vice versa using one).
6: In Gen 8, there are special mints which change the nature of a pokemon. Or rather they change up which stats are affected by the nature, as the nature technically remains the same. A Adamant Mint makes it so that a pokemon gets the 10 percent boost to attack at the cost of 10% loss of growth to special attack, but the actual nature (lets say timid) stays the same despite the change in the stats by the mint.
7: In Gen 6 they added two different bottle cap items which if used at level 100, a pokemon's IVs get maxed out. The drawback being that the cap affected pokemon cant then pass those IVs to a baby as they are artificially enhanced. It also doesnt affect the hidden power of the pokemon who uses them. A normal cap raises one stat to max, and a gold bottle cap boosts all IVs for a pokemon.
8: In gen 8 quite a few pokemon gained moves that drastically improved the viability of them due to the sheer amount of moves. A great example being that Venusaur can now use Earth Power. I figured this is especially important to note whenever you get around to adding move tutors to the game based on a previous comment on move availability.
Thats all I can remember currently but I figured I'd share this since these are very helpful features for post game stuf in particular (assuming you plan something like a battle frontier). I know you likely wont be able to add most or any of this given your schedual but I figure its worth looking at for reference.
