CRASH
I'm DYING to here the mii costume/Crash leaker respond to the NOA guy's statement about "No Crash, No Tracer". If the mii costume/Crash guy sticks to his guns about Crash being #5, **** is bouta get mad interesting. Regardless, I think it's fair to speculate that Crash is in the pipeline.
REIMU
The Touhou tracklist is a MAJOR curveball. It appears that this has been in the works since Nov 2018, according to the "leak" shown in PapaGenos vid, so theres a great shot Reimu could be #5. This could also all lead back to that leak where some guy said a girl with a flying weapon is coming to Smash (idk Reimu's weapon, but this could be what he was talking about regardless).
RYU
Shifty and Brew have the same source who said he was fighter #4, but Papa made a great point in his video about how leakers tend to get the order of the fighters wrong. However, this "leak" occurred right around when Ryu was added to Warriors Orochi 4 ULTIMATE. Just something to keep in mind.
OVERALL
IMO, I see the current running for Fighter #5 at 45% Reimu, 35% Ryu, 20% Crash.