There's something that I just noticed.
If you compare the map of Ultra Sun and Ultra Moon to Sun and Moon, you notice that the rain cloud above Po Town is gone.
You also notice that the Pokémon League has already been built on top of Mount Lanakila.
You can also spot some moving objects in the water that would either be Pokémon or boats, they're black, so this might have something to do with Team Skull, maybe? Nope, upon further inspection, they seem to be a herd of Wailord.
But, the empty plots do appear to be filled.
The volcano at Wala Volcano Park seems to no longer be spewing ash into the air.
So, these plots have been filled, that is for sure.
Po Town no longer has rain, as what I'm assuming from it.
This could mean that Team Skull may or may not be in the game, and if they are in the game, there's the likelihood they're situated on Poni Island instead.
This is my analysis of the maps.
(This is the old map of Alola from Sun and Moon, compare it to the new one from Ultra Sun and Ultra Moon and you can see what I'm talking about)
>>33324185
OP here, here's the Ultra Sun and Ultra Moon map.
Maybe in this universe Bulu never had an autistic shitfit and the old Team Skull never disbanded
What's the black hole!