Well, what the Pikmin, Paper Mario, and Pokemon reveals show is that now everything is basically on its own, operating individually, and not tied to a larger, company-wide event. To that end, Smash reveals also wouldn't need to be contingent on either a Direct to happen or Nintendo having their whole plan together. It's just about Smash itself being mostly on-track.
If we assume that FP7 was to be revealed in June and released possibly next month, and the following character was to be revealed at the typical September Direct and revealed in the months to follow, even if you get rid of all those other plans, the Smash release schedule might still be intact, as well as the ability to have dual reveals, thanks to FP7's delay. Because they're going to have to show that character either way.
Yes, normally a dual reveal wouldn't just happen apropos of nothing. It would take an E3 or a Smash Direct. Or at least a normal Direct. But normally we actually get E3s and Directs. Normally Sakurai doesn't film things from his house. Normally FP8 might be a month or two until reveal anyway.
All we really need for a dual reveal is for the Smash schedule to maintain course. Not Nintendo's in general. Because it's not like there's any guarantee they'll have a Direct ready by FP8's release, and like you've demonstrated, everything is handled on a per-case basis now.
Obviously that doesn't mean it will happen, it just means the timing might line up given how plans have already changed. Like I said, it's also a possibility we don't even see FP8 in 2020 at all. For all we know they could wait to reveal FP8 until just prior to release, as is now the probable plan for FP7. Or maybe Smash has actually been impacted by delays.