I'm willing to believe partially what the chinese leaker ("riddler" was such a dumb nickname, it was barely riddles!) says, but I'm willing ot bet some of this details are a bit off. Part of that dealing with the usual game of telephone/development changes (present in his original set of leaks, such as mentioning greninja forme changing based on z crystals), part of that deal with their apparenty disinterest in the USUM game. So he probably wasnt as receiptive to details.
For instance, the RR part about past villains from worlds where they won. I can see that actually meaning some villains who may/may not be from other worlds, possibly not where they won because that would mean some weiiiiiiiiiird things for Archie & Maxie (who were instantly retentive the moment they saw they caused the apocalypse and at heart did seem to care about the state of the world), not to mention Cyrus (wanted to destroy & recreate the universe) & Lysandre (fantasy nuke the world). Which...basically just leaves Ghetsis and idk the Johto admins? If they come from "they won" timelines. I cannot envision N ever going with any part of Giovanni's anything, period.