Alfrodo

I doubt thet next trailer will be soon. Like Wakeless Dream said, those screenshots were probably shared to compensate for the cancellation of Missing Link, because they CAN'T share a trailer/teaser just yet and because it's been 3+ years since the first and last time we got KH4 news. Multiplayer would be a weird move, considering it's only been in Days and MoM and this would be a main numbered title, but I wouldn't be against it. About seeing the Guardians of Light + Riku + Kairi, I'm not sure if you're talking about the game or the trailer. If it's the former, other than Riku, I don't really expect the rest of the guardians to be in the game at all. Considering how most of their stories are done and Kairi has been written off into a corner, I really only expect to see them in passing going forward, MAYBE in this game. The ones I think we may see more of going forward are Ventus (because of UX stuff), Axel and Isa (because of Subject X, possibly Skuld) and the people they hang with might follow them by extension, but that's it. If you were talking about the latter tho, as much as I want them to show Riku in the next trailer I'm not 100% sure we'll get that in the next one

It literally says the name in the article

There's also the series logo on the head of that dragon. But that might just be a random heart Idk