One doesn't need to concoct new reasoning as if arguments had some arbitrary expiration date when the existing reasoning still stands.
Meanwhile...
Perhaps someone who shows up to say things like this when not casting aspersions on the thread ought to pontificate less about maturity and civility.
I mean, you can take hyperbole literally if you like, that's up to you. I tend to hyperbolize how I feel about something to bring humor to it, something that is difficult to do when text is the sole form of communication, made even more difficult with company that automatically defaults to a negative opinion of you.
To be fair though, I don't actually hate the game that much, even though I do think it's incredibly manipulative of children. Between that and it's success causing Epic Games to be short sighted and kill off a game I was much more invested in, I have no qualms about it. It has it's own level of appeal, it's own level of skill, and it gets a lot of cool stuff.
Though I can understand why you would assume I have an irrational hatred toward a video game, as it seems the irrational is more commonplace, but having said that I would figure my open-mindedness of Ultimate's inclusions and insightful posts with deeper thinking would suggest that I tend to be less reactionary than your average internet user.
I will say that Fortnite not getting a character in Smash is simply a victory for everyone though, as it's proof that Minecraft achieved something outstanding and that run-of-the-mill games who have momentary popularity don't equate that and that Nintendo hasn't fallen so low as to capitalize on something like that in the faces of their fans.
As for the Mii Costume thing, you are just flat out wrong. You have been proven wrong on the existing reasoning multiple times, it's just that you changed from the initial quota many times already that you have probably forgotten already. The original quota was 'If any content from the franchise of the character you want exists in the base game, they have no chance.' and after that failed when ARMS was announced it was changed to 'Content of your character kills their chance'...which then also failed with Min Min. Then it was changed to exclude Spirits from the base game, a literal PNG, but Mii Costumes and Assist Trophies were the death sentence for sure. So, just to clarify, Mii Costumes weren't even the starting point of the argument, and this stance already failed twice, yet the mindset is the same.
However, a simple dive into Sakurai's previous development attempts proves that he has always attempted to get the 'main character' from a game or franchise to best represent the series in Smash. This means that, when he went forward to negotiate for ARMS, Spring Man was on the table and clearly who he was going into the negotiations for originally, even though Min Min was the most popular and Ninjara was his personal favorite. It was the producer's wishes and ideology that won Sakurai over to choose Min Min in the end. This very fact alone means that neither his AT nor his costume stopped him from being chosen, but let's get to the more obvious ones.
Sakurai said that the game can't handle Rex AND one of the girls moving and fighting about at the same time at any given time, so instead of scrapping the character they made a design choice to just pick the girls and include Rex in what areas they could. Now, does that sound like it has anything to do with his costume? Don't forget, this was when the narrative changed the quota again: now it was 'Third Party costumes deconfirm, but not First Party' and no single person could give a real answer to back that up. It was a silly argument that was simply adjusted to fit what had happened without any sound logic behind it, because logic at this point would suggest that costumes just aren't a deal breaker.
Then, we got Kazuya, and Sakurai said he was chosen because of the Devil Gene which allowed more creative freedom to make him truly fit into Smash. If you recall, Heihachi was attempted for Smash 4 but they couldn't do it to satisfaction, and so it seems a similar situation happened and they went with Kazuya instead. Once again, we have proof that Heihachi's costume had nothing to do with it, so that kills the argument again...yet, and correct me if I'm wrong, but the quota was changed to 'costumes of the character deconfirm the character themselves but not other from the franchise' I believe? What a pitiful state this argument is in, it is barely recognizable from it's original state, and honestly it makes no sense.
So first off, this contradicts it's previous form, which was that 'First Party Don't, Third Party Do' because now it includes first Party costumes again...which was something you guys already ruled out. It also is just wrong, because of all the information we have that points out that the costumes had nothing to do with their exclusion, which is essentially calling Sakurai a liar, something you guys chew people's asses about when they suggest Sakurai could be doing when it comes to content after CP11. This means that you are making the same claim as those who bring evidence for more content past CP11 but insist that they cannot make such a claim while you can...rules for thee but not for me.
Let me add something else: this implies that every single costume was chosen with the intent that these characters we not getting in. In other words, you are implying all the costumes were chosen after all the characters, which we not only don't know for sure but actually have evidence that this isn't the case with the returning costumes. Having every single Third Party costume return in random intervals is proof they always planned to return them all in some way, something that does not require characters to be chosen beforehand but rather just choosing where and when the costumes return.
Finally, this train of logic doesn't even fully apply to returning costumes, as they didn't have to be freshly made for this game. We have viewed them as killing off a characters chances since Smash 4 because, at that time, they were new and there was no reason to make a costume and the character playable (other than money of course). However, when you combine the fact that they were not new and had very little changes made to them with the fact that they were all planned to return and thus wouldn't interfere with character decisions, returning costumes really don't have the same weight as brand new ones. This would be even more true for them and for costumes that came out this cycle for the next game of the series or even more DLC, were it to happen. Also, the simple answer again, if they think they can make good money off it they should do both a costume and the character just to make that much more money, and of course they should do the costume first because it will get more sales than if it releases with or after the character.
In other words, assuming a character has a lesser chance just because of other content related to them appearing in the game while development for the game is still actively ongoing is foolish, as anything can change. Such gatekeeping is folly and too broad in scope. Focusing on the specific pros and cons to each character's chances is a much more efficient way to get closer to the answer, as well as thinking in terms of the company and as a developer rather than with the mind of a fan and removing your own biases. For example, both Sephiroth and Kazuya had signs from a while back: Cloud lacking a lot of content in comparison to other packs, Sakurai dissatisfaction with this, and the overwhelming success of FF7R coupled with Square's more consumer-friendly approach were all obvious signs for Sephy while Heihachi's failing to be added in Smash 4, the success of Tekken 7 and how much help Bamco has been with aiding in the development of the last two Smash titles being perfect signs for Kazuya.
I think plenty of these signs are out there for CP11 as well, so we should all have it narrowed down by now, though I suppose time will tell soon enough.