Lets see what else they'll reveal for USUM judging just by the existing trailer teases

1. Light creature from the artboxes (most likely another Necrozma form)
2. More on new Ultra Beasts because we dont even have official artwork or any basic info on them.
3. Who are the people from the recent art
4. More on areas/ultra spaces for UBs and if they're all as small as Nihilego's and what looks like to be Kartana's
5. Whats the Pikachu Valley for/about
6. New possible Z-moves for Mimikyu and Togedemaru
7. Whats the Lt Surge looking gym is for (most likely some gym showcase in alola done by Kukui or gym simulator)

Thats prrobably all about the stuff we saw in the existing trailers