I thought Zippo was talking about Travis until he said "it's a weird situation." There's absolutely zero ambiguity regarding Travis' parenthood. I really can't think of anyone who fits all of Zippo's clues besides maybe Geno, but Zippo's been so vague and borderline contradictory that I don't see the point in slaving over his words when we're only a day away from the reveal. It could be anyone.
This was sort of alluded to in a few of the posts shared between me and 11.0 but the big questioning point that a lot of Suda fans have had about No More Heroes is that, even setting aside the fact that the series was only brought back because Nintendo requested Suda to make it, a lot of us have been kind of confused where Grasshopper would've found the capital to reacquire at least the majority rights to the franchise (and I stress this because at the early 2010s the full rights were still attributed to Marvelous) when signs pointed around late 2018 that they'd substantially downsized on top of Nintendo now being a major client for them, much like GungHo and Kadokawa (the former of which are their parent company and the latter of which were an investor during the seventh gen). NMH3 having a budget and TSA having all these cross-company collabs (not just indies but partners like Capcom, EA and animation studios like Kamikaze Douga) despite being an "indie sized" endeavor was suspect back then and even more curious moving into NMH3 given that Grasshopper themselves are still really small as of present.
The popular theory for the time being was that Nintendo may have signed a marketing/distribution deal which may had resulted in enough money for them to basically allow Grasshopper to take the reigns back on the franchise, with the series mainly targeting Nintendo platforms. Passing Assassin made the point last night that Zippo's correction still works in Travis' favor given that TSA was eventually ported to PS4/Steam multiple months after release at Marvelous' behest, though this was clearly a much smaller priority affair and the series is still mainly Nintendo oriented as of right now. Theoretically NMH3 could eventually land on other platforms but given the TSA ports were an absolute sales bomb and since it was a small game less designed with Switch's capabilities (NMH3 from what we understand is most likely going to make use of split joycon controls a fair deal), it's not looking too likely that NMH3 will get ported despite the option being there. With those circumstances I think it's pretty fair to assume NMH's state is kind of "complicated" despite Grasshopper now being partial co-owners.
That being said, I agree with you that it could be anyone at this point. The bar for "third party with a strong Nintendo connection" is a pretty easy one to cross, and only really discounts names like Dante, 2B, etc. It even works to Arle's favor given the SNES Switch offerings and Puyo Tetris making it west thanks to Switch.