From what I understand with Polar Panda's rumor, their source originally stated with certainty Steve wasn't in, and then clarified that they were rumors. But I was curious as well other insider's thoughts, even as speculation, given Ryce has been the first insider I've heard speak positively about Banjo's chances. Everyone else either hasn't said much, or are doubtful, even those that are hopeful of his inclusion. But that's back when I was keeping track, prior to Ultimate's release, and curious if the mood has changed since.
Regarding the Polarpanda rumor, I have a feeling that this journalist dude was intentionally backtracking to save his butt from the effects of breaking NDA. Im not about to fully believe Panda or this dude, but it would stand to reason that he would go public in his statements that they are rumors. Saying Steve is 100% out wouldn't really break NDA, but saying that Banjo's in would. For all we know he could be completely right, and just backtracked to mount a legal defense if Nintendo Ninja's or Microsoft Mercenaries appear to slap legal punishments.
For the sake of my theory, lets assume Banjo's in. This would have to involve a broad NDA agreement slapped on all parties that know or are trusted with the info of Banjo's inclusion as DLC. Anyone, be it company, or person that knows Banjo's in would be covered by the NDA and would be subjected to punishment if they leak any info out. This includes Nintendo, Microsoft, and any other company involved. This is why the Banjo-Kazooie loot-crate event looked so weird. From what I know about current Banjo-Kazooie merch, it's possible that the item was Smash related since Loot Crate often distributes exclusive items. The item being taken out could've just been standard Loot Crate shenanigans. It looks suspect when the item was taken down at the same time as the Banjo for Smash meme tweet was taken down. I suspect that dev time for Joker took longer than expected and that the supposed Banjo for Smash reveal would have to be pushed back. It's fair to theorize that these agreements take months and months of prep time to go down, meaning that Nintendo and/or Microsoft shared the Banjo info and commissioned Loot Crate to showcase an item related to Banjo as a Smash bros fighter. It's not the best theory, but it's possible that Loot Crate would've broken NDA if the item was released.
Again, this isn't me claiming that the Panda or Lootcrate event is 100% true. For all we know this crap could've just been one massive coincidence. This is just a theory I have that might explain why the events unfolded the way they did. I do wonder what the pulled item was. Some anon on 4chan claimed it was some beer coozy, but when I pressed for a source he got surprisingly quiet so claim discarded.