I find it funny that people complained so much about Little Mac in Japan. It's like... when you think about it, only three characters in Ultimate cater exclusively to the western audience - at least that we know of. They seem to be Mac, Ridley and Dark Samus. The rest either has japanese or global appeal.
Personally, I don't see another western character happening in the FP. Unless we get another Japan-focused reveal like Dragon Quest.
Regarding Nintendo characters being looked down upon for the FP... I think this disappointment was born in the final direct, for me at least. Even though I went with Box Theory as my "worst-case scenario", I was still disappointed, because so many viable and popular characters were either Assist Trophies or Spirits, meaning they were cut off from being DLC. We all know how the Isaac and Shadow fanbases felt being deconfirmed at the last minute.
Because of this, and due to the fact that we have no information from an official source on Spirit deconfirmation, that leaves very few possibilities for a Nintendo character that will make people happy. And pretty much any third party would turn more heads than a Gen 8 Pokémon or someone from the new FE, so I think that yes, we're just getting third parties for DLC.
I don't think another Pass is happening. It's possible, but I wouldn't hold my breath. Based on how Sakurai doesn't like overextending development cycles, this is probably just the final hurrah and that's it.