The claim that Mysterio (who appears to be a good guy AND has super-powers- the original Mysterio is a villain and does not) is from another world changes everything up. If this is true, they're introducing multiverses into the MCU, which will allow for crazy shit to happen (and is an easy way to bring in the X-Men and Deadpool, lol) and maybe even multiple versions of characters...including characters who died coming back from other realities. HINT HINT. But it also could be Mysterio being full of shit. In fact, some already are are speculating that this being a trailer means it's all a ruse and that the Nick Fury in the film is NOT Nick Fury, but might be another classic Spidey villain, the Chameleon. But then how would they know who Spider-Man really is?
And if there is multi-verse stuff in this movie...the name "Far From Home" takes on a completely different meaning. The black-suited Spider-Man in the trailer...did we see his face in any other trailers? If not, maybe that's MILES. Holy fuck, totally excited now.
Betting that's not it and it's just Peter though.
This can be backed up by a mini-series Marvel did a few years ago, BTW, called "Spider-Men." Main comic universe (616) Mysterio found a way to access what was the "Ultimate" universe (separate comic line based on the various movies and is where the design for Sam Jackson Nick Fury came from, plus Miles Morales as Spider-Man) and the Mysterio in the Ultimate books was actually the 616 guy remote controlling a robot. Then the two Spider-Men meet each other to stop him when a portal opens. People will go insane if this actually happens.