itch.io

1. It seems that there's no Drop Mechanic

2. You'll need to dismiss a character then hire another (the followers can be Brock, Misty, and the regional girls [why Leaf isn't this game I do not know]); They level all their pokemon after with got a training session with them (why is it once a week?), and their pokemon line up improves with the relationship level

I think she's in Galar with Nessa

Go to Dewford and get in the boat that goes to other regions

Fossils is most likely found on pokemons wearing bones. I found 1 on a Vullaby

Evolution Stones are found in wild, according to the release.  I found a shiny stone on a shiny (and most likely only on shiny pokemons)