TBH, though I'd love to be wrong, I don't see it happening. The reason we latched onto Travis being in pass 2 is because Suda already politely deconfirmed Travis. As we know, game developers love to tow that tricky line of playing coy without breaking NDAs in order to make eagle eyed uber fans excited when a reveal is made, but in most cases devs take the precaution to not outright lie to their fans, for better or for worse, since that's cheap surprise bait and makes you look untrustworthy. I think, so far as we know, Suda was saying that, AT LEAST for pass 1, he hasn't heard from Nintendo asking for Travis is in. If he was, Suda probably wouldn't say anything at all.
Odds are, if Travis is in, it's going to be in whatever happens after fighter pass 1, and in a way that almost works better imo. Travis could come at a later date, which could coincide close to or after the release of NMH3, which works as Sakurai throwing a bone to a good friend, but also as a promotional pick for a game Nintendo is trying to boost, not unlike Bayonetta's status with Bayo 2, where whadaya know, Bayo also made it into Smash 4. Travis comes to Smash around the release of NMH3, people are now looking at Travis in Smash, and by extension will be looking at his series and for an entry point into it if they think he looks cool. The only thing that would make it better is if remakes of NMH 1 and 2 on the Switch were announced sometime after the release of NMH3.
If Travis doesn't happen in Ultimate, it does look like Nintendo is treating the No More Heroes franchise like Bayonetta where they're backing it, possibly provided it stays a console exclusive, which I do think bodes well for Travis' chances in a future Smash title after Ultimate if this pays off and No More Heroes as a franchise soars to new heights with a fandom bigger than it's seen before, which seems to be happening with Bayonetta 3.