I was surprised that Freeza didn't actually betray them, but I'm glad he didn't as swapping universes made no sense since being able to do it hasn't been established.
I think it's just a likely that they will Vegeta him than have him do a betrayal at the end to get the wish. Only way he can win is to push Jiren off at the end once Goku weakens him, wish to be stronger than Beerus or whatever, then have Goku be honour bound to ressurect him after since Freeza won the tournament for them. That won't happen because Goku is going to win and wish for the universes to be merged rather than erased.
Personally I'd rather see Freeza work with the others as an ally and part on good terms, making future conflicts with him more interesting, but I expect him being alive to be resolved in some way by the end of the arc - so probably a failed betrayal at some point.
I don't understand the preview since it seems like they have Goku fighting Ribrianne AND Jiren, which is endgame, but lots of potentially lower tier fighters like the Universe 6 Piccolo and Lord Slug are left.