The only questionable one to date was that we would get Minecraft content, which many translated to Steve(?) Being playable.
Personally though I think he will just end up as a Mii Swordfighter skin, even back then too.
Wouldn't be completely surprised if more Microsoft characters join Banjo later on. Of course this rests on one big assumption: That there will be more. And I dunno if Sakurai's up for that - the only possible piece of evidence we have are the datamined WoL slots. Still, the WoL slots allow for three theoretical Fighter Pass seasons - Steve and Chief could both fit into a hypotheoretical Season 2 and 3 seperately.
I've talked about the Switch's upcoming release in China - and my assumption that Smash will release there. There's no release day for the Switch just yet -
the Chinese government hasn't approved the Switch's hardware yet. I should note, Nintendo's working with a goddamned megacorp on that. And said megacorp's integrating their own Skype (WeChat) into the Chinese Switch. If I'm a betting man I'd put the Switch's Chinese release at early 2020 (Late March / Early April 2020. I'm being conservative here.), with Smash around launch or not long after that. The tweet linked in the article notes that a lot of work's being done, and they did show off BotW there, but no release day yet.
It'd be
really strange if Chinese Smash players only got to experience already-released DLC. And no further DLC past Feb. 2020.