Although I did mention "regardless of whether Ryu makes the fighter pass or not" my trail of thought when I mentioned keeping support high was more along the lines of keeping Hayabusa's name on the radar after the momentum brought about by the leaks, so he might gain more traction later down the line as a primary 3rd party pick for any future smash instalments; similar to how Rayman gained a lot more attention after the smash 4 "leak" and as a result, his name started popping up more frequently, and overall had a warmer reception from smash fans (although I was considering this as a worst case scenario if he didn't make it in as DLC for ultimate). But I completely agree that as it currently stands, his strong Nintendo legacy is definitely a factor that towers over fan demand, that and being one of Koei Tecmo's most recognisable character are some of the biggest factors that'd lead to a playable inclusion!
On the upside as many of you have mentioned, Shifty has a very strong track record, so his sources clearly have some credibility. Although his timing has been off, such as last year's November direct date (only by a single day), and more recently Hayabusa as #4 in the fighter pass, the actual information he's provided has been more or less spot on! (Nobody just guesses Marx as a boss, all 3 final characters and especially the addition of a bonus character in the form of a playable Piranha Plant!)
On multiple occasions leakers have had correct information but incorrect timing, e.g. Gematsu leaker with Shulk in Smash 4, Vergeben with Erdrick being the first fighter in the pass, Papageno's source giving the impression Banjo was going to be a base roster character etc.
So in short (ok maybe this isn't short lol) I still have a great deal of confidence that Hayabusa will eventually make it into Ultimate! While of course I still can't be 100% certain, I feel the real question is will it be via fighter pass slot #5?
lol