If you ever want Emerald with some quality of life improvements (e.g. HMs not being necessary to actually teach; you can use them in the overworld as long as anyone in your party can learn whichever move), I’d highly suggest the Emerald Seaglass ROM hack.
I’m mainly bringing it up because the art is absolutely gorgeous. So if you ever want to dive into Emerald again, give it a shot.
You can play it on a variety of GBA emulators, so it’s pretty simple to get running. A few good Android ones, I believe there’s one called Delta on iOS, and there are several for most desktop OSes (included Linux).
I mean, the Z-A previews definitely showed a similar art style, but the battling gameplay is completely new. Dodging out of rollout looks great.
If it’s in Lumiose, I really hope the “you’re not the one” hex maniac girl is back and they actually resolve that plot thread. I doubt it, but who knows.