I'm gonna predict the following:
That the English set will have a FA and a Rainbow Rare version of Tsareena GX. As well as other Promotional GX cards coming between now and the release.
Olivia FA and cards form the SM4+ set are possible but not as likely.
Possible cards (besides Type-Null and...
It seems the pattern here is to make pin collections for GX pokemon in the set, but use non-GX promos. But there are only 4 GX pokemon (Mewtwo, Entei, Zoroark and Raichi), so either there are only gonna be 4 pin collections or they might also use Pokemon with Shiny counterparts (which would mean...
On the one hand. Unlike Tapu Koko we can get a Shiny-type Null in game, and there hasen't been word on any Shiny Vocaneon events (for reference Vocaneon is Shiny-locked yet has a Shining card in Shining Legends).
Then again, Shining legends is a subset so maybe it isn't worthy of a promotional...
XY-on would had been the most likely change. With how late changes to expanded would be, any shifts to Expanded's set rotation would likely go by Generation.