I think the biggest question then falls on:
Why would they mess with the playlist a solid month and a half before a supposed Direct in mid November?
Fix a typo, minor changes, perhaps an error on someone's part, it's hard to say. I'm hesitant to bank on the playlist simply because we have no proof of it happening prior to Isabelle. If it happened for 8.8 and could be solidly proven along with happening with Isabelle, I'd probably be more open.
As for the new icon on the website, that could simply be built in functionality. Perhaps the site is designed to remove the new tag after a certain amount of time has passed? I honestly don't know on that one.
I've been behind the idea of a end-of-October Direct for a while now, however, I'm also not completely writing off the possibility of it being further ahead in November. I constantly bring up the notion the game will get a preload, but there is the possibility it may not, no matter how slim. Truth of the matter is, there isn't really anything ironclad to lock down when we should expect the final info dump. Last month was a little easier to bank on thanks to Nintendo's need to discuss NSO (I admit I was overly pessimistic when I dismissed the idea; it was very obvious in hindsight). The final Smash Direct, however, is hard. Nintendo has few, if any patterns they actually follow, and even when they do they break them all the time. I'm not dismissing the potential of October, it's still what I believe is gonna happen. However, I will also admit I don't have much in terms of evidence for why I think it will, other than how games in the past year were handled and a gut feeling.