Time to put on my tinfoil Geno hat for a second.
As we all know, the Square Enix Mii Outfits from Smash 4 have still not returned in to Ultimate. Obviously, this is a huge indicator that we could get another Square Enix rep, but this theory kinda extends further than that. This theory I believe can help narrow down who we could possibly see in the last four remaining spots.
We just recently got another Microsoft rep with Steve. What is notable about this is that in the last Pass, we also had a Microsoft rep with Banjo. Now, when they went over Banjo's wave in the last Pass. their was a whopping total of ZERO Mii Outfits related to Microsoft or Rare, and Banjo's wave was the first instance of a "grab bag". My reasoning as to why they skipped over adding any Microsoft Mii Outfits in Banjo's wave might be because they already knew they were gonna bring along Microsoft Mii Outfits with Steve, so they just waited until then to add them. Now, some may point out that Microsoft isn't a returning third-party and they were introduced in Ultimate, but even as a new company being introduced to Smash, it was still pretty notable that their was a lack of Microsoft Mii Outfits and it was by far the biggest thing going in favor of us getting another Microsoft rep, which obviously did eventually pan out.
So, with this in mind, the only actual returning third-party from Smash 4 that STILL doesn't have any Mii Outfits is Square Enix, aside from the Dragon Quest ones. Now, some may point out that the Dragon Quest outfits might put a final nail in the coffin to this theory, as those ARE Square costumes. BUT, I feel like this only applies to companies introduced in to Ultimate like Microsoft or SNK. Obviously, Microsoft had nothing in Smash 4 so of course their would be no returning Microsoft outfits. In this case, Square did have costumes in Smash 4 that COULD have returned, but they have not, SEVEN WAVES LATER. So, I think if you are a RETURNING third-party from Smash 4 who has no returning Mii Outfit, then that is a good indicator that we will get another rep from that company.
However, this theory isn't all good news though as I personally feel this could deconfirm potential characters. In the last Pass, the companies that had reps were SEGA\Atlus, Square Enix, Microsoft, SNK and Nintendo. Joker's wave introduced Persona-themed Mii Outfits as well as the Knuckles and Tails Mii Outfits, which is why I think a SEGA rep sounds extremely unlikely, since why would they add another SEGA\Atlus rep if they didn't plan on saving those costumes for another SEGA rep? This theory also shoots down a potential SNK rep since Terry's outfits featured a wide array of SNK costumes and featured the last remaining SEGA outfits, even furthering the nail in the coffin for a potential SEGA rep. [And besides, Terry's entire Challenger Pack was less so about Fatal Fury, and moreso about SNK as a whole, so I highly doubt another SNK rep is coming]. Now Nintendo is an interesting case, but I don't think this theory really applies to them, as this is moreso about the third-party companies. Not only that, but I think this theory can also deconfirm characters from newly introduced companies like Ubisoft and Bethesda, since both companies have Mii Outfits.
I feel like this theory was kinda tricky to explain but let me sum it up for you all. I think if a newly introduced company, ala Microsoft and SNK, does NOT get any Mii Outfits AT ALL, then that is a good indicator they may get another rep. Obviously as I explained, Banjo's Pass had no Microsoft Mii Outfits, and Steve eventually brought over Minecraft outfits. And if you are a returning company, ala SEGA, Capcom, Namco and Square Enix, then the best way to tell if these companies may get another rep is if they, as of right now, do not have any of their returning Smash 4 outfits in Ultimate. The only one of these returning third parties that do not have any of their Smash 4 outfits back is Square Enix. Namco is an interesting case since they develop Smash, so like Nintendo, I'm not too sure if this theory applies to them as well. SEGA sounds unlikely since all the SEGA outfits from Smash 4 have returned, and while the only missing Capcom outfits are the Monster Hunter ones, Capcom is still getting new outfits very frequently, as well as returning outfits from Smash 4.
So with this theory in mind, I predict that the remaining companies to get reps are Square Enix, Activision, Namco and Nintendo. I already explained why Square Enix will most likely get another rep so I'm not gonna go to in depth with that. Activision, however, goes along nicely with this theory because they are so far the only major third-party company that has YET to get any representation in Smash, which yes, includes no Mii Outfits. While Namco does have returning outfits, they develop this game so I don't think they really apply to this theory, and Nintendo is Nintendo.
As for my exact character predictions for the rest of this Pass, I predict the Square rep will be Geno obviously, the Activision rep will be Crash, the Namco rep will be Lloyd, and the Nintendo rep will be Rex from Xenoblade.
This is definitely an interesting theory of mine, so I hope you all enjoy it. I also hope you all understand this theory since I'm not too sure if I explained it well enough. I know this was a rather long post, so props to anyone who has read the full thing, since this took me almost two hours to write-up. I am hoping this pans out in the end because I'm not the best when it comes to predicting things, but it is fun to make theories and sometimes, theories can mean something. We just need to wait and see.