If I had to guess when Challenger Pack 6 is coming, I'm thinking mid-late June to the start/first week of July. Smash, Pokémon and Animal Crossing are gonna hard carry Nintendo through these trying times, being the biggest releases of the year.
Challenger Pack 7 before 2021 is starting to feel like a pipe dream, though. In terms of release, at least. Reveal is possible, but I think Nintendo is gonna spread them out. And once the virus truly starts getting reduced in potency, we'll see it speed up significantly and it'll neatly wrap up by late 2021.
And my current guesses:
#6 will be an ARMS character with base game content. Spring Man, Min-Min, Twintelle, Ribbon Girl or Ninjara. If it's not one of them, Dr. Coyle or Max Brass free.
#7 will be Urshifu or Calyrex. I see no reason for Nintendo not to pick a soon-to-be prominent Pokémon from what's going to likely end up as their biggest (or second biggest) release.
#8 will be a more neutral third party. Somebody like Ryu Hayabusa or Bill Rizer: not necessarily currently big, but somebody who is very important to gaming in some way, shape or form. Kinda like Terry Bogard, think of it like a "thank you gift" for good current relations with Nintendo or bouncing back into the gaming industry.
#9 will be a major Japan hype third party. This is why Arle wins, but Reimu could go here. Or a Tales rep. If I didn't mention a Japanese third party character (think Dante, Heihachi, Sora), they could take the place of #8 or #9.
#10 will be a widely celebrated western third party. Crash Bandicoot, Master Chief, Steve, maybe even Scorpion if they wanna go off...
#11 will be another first party character, one with base game content as well. Waluigi, Bandana Waddle Dee, Tingle... something more low key than the previous ones. Could've been Tom Nook, but I think the ACNH Spirit Event took away his best Spirit material, and with it the best reason for his inclusion.
Let's say we get this set: Spring Man, Urshifu, Ryu Hayabusa, Arle Nadja, Scorpion (would put Crash here, but he's on every prediction list and I want to be different) and Waluigi, in the order from #76 to #81. Joining the trend, what would people think?