Pokécharms

Mainly because, during the trailer, Grookey was playing the drums on some rocks. The one person I remember being into rock was that Poison-Type Gym Leader, Roxie, in B2W2. Scorbunny reminds me of a soccer player and it's super speed is something that Electric-Types may possess. Sobble reminds me of a Ghost-Type with how sad it looks, and I know people who are depressed will listen to music and sing a lot.

TL;DR: Grookey's final evo is a Grass/Poison drummer monkey, Scorbunny's final evo is a Fire/Electric soccer player, and Sobble's final evo is a Water/Ghost opera/theatrical singer (or a singer of some sort, but I remember opera was pretty big in the UK).

Also, Grookey's little hairs are up in a similar fashion as Roxie's. XD but instead of a stick, Roxie has little beads that keep her hair up like that.

Huuuh, interesting, I honestly think Grokey might be Grass/Ground but those similarities to Roxie possibly meaning it'll be Grass/Poison seems really interesting.

And that idea of Sobble's evolution would more likely be a musical signer more so then opera since I don't recall a whole lot of popular opera lately around here.

Well, I'm pretty sure that theatrical singing to instill emotions in others of some sort will be the basis of Sobble's final evolution. XD And, if I remember correctly, it was pretty big somewhere around the 1900s, but I need to check that... on my lunch, since I'm working. XD

There's a Royal Opera House in London where famous Opera singers (some having their roots in the UK) come by and sing and stuff.

Hell, there were quite a few opera singers in Britain's Got Talent. Its probably not as big as football (not American) or being a part of a band, but it's still a thing.

I think Grookey will turn out to be grass/ground (Because of the stick it has, and the colour in of its legs and hands, I think it's final evolution might look like a Morris dancer. Morris dance is something that's 100% uniquely British, and it is often performed with sticks. That, and Morris dancers commonly wear leather gloves and shin guards, with bells on them.)