I do think because June is the 3 year anniversary of the Official reveal of Smash Ultimate (Not counting the reveal of Smash Switch), that we'd probably get the Reveals in June.
Like I could see even with a May Direct, that they give us the Date of a Smash Broadcast, instead of a Reveal
Well your tether to rationality has always been hanging by a thread so I'd say that'd be par for the course.
To explain my Rationale, Here's How I see
Development is winding down heavily it would seem. If FP2 is it for Ultimate (and I believe that's the case, as of Right now), then personally I think the Last 2 Fighters are either very close to presentable state, or already are in that state
When it came to Base Roster -> FP1, and FP1 ->FP2, I believe the team went straight into each Period of Development with no break. Some people get taken off course, but pretty much there was always something next, so the Focus had to have been placed on the next character in terms of what needs to be developed
Since These Last 2 Characters are supposedly it, with no new Development being planned in the future for any content of Ultimate, their focus, after the release of Pyra/Mythra (or even right now since they might be finished 100%) will be solely on the last 2 characters, so we could see a Speed up in the development of them both, to the point where we could see Simultaneous release
Of course, there are alot of variables to that, Since not every character has the same variables to their development, with differences in amount of effort required to model, balance, animate, etc. There's also the fact that there probably staff members that are being taken off as of now, and not even talking about ones like the Render Artist, Mural artists, Modelers, etc who possibly might already be done by now, but even members of branch of Active development like the balancing and animating.
I also think a Final Smash Presentation is possible, just like Smash 4. I do know the reason they did do grouped up releases like they did was because the 3DS couldn't update so frequently, but they might also might and be able to finish very soon, and releasing both of the last 2 could be beneficial in their own way. yes