I could see Lorde and Chappell being there, Olivia feels too big though. Also got doubts on Nick given he's literally playing Barcelona like, in a week. Bon Iver doesnt seem to be touring anytime soon either with his recent comments in interviews. Cindy Lee in the undercard is also sus as hell given they cancelled their tour.
Also worth noting they did say one of their bookings this year was a "wildcard" booking so that alone could mean set aside your expectations for what is and isn't a Trees band
I still do think Bloc Party is a Trees band though, they've had bands like IDLES and Nothing But Thieves before too which I wouldn't normally associate with Trees
so my current guesses are Bloc Party + Kneecap, Amyl & The Sniffers + whoever the next clue is
I really feel like Alexisonfire are gonna be there so they might be the Saturday, we'll see when they drop that clue tomorrow