I didn't even know the Game & Watch forward smash was a thing, but apparently happened after the final Smash Direct. Odd how I never noticed it. While I think the controversy is mistaken (erasing potentially prejudice stuff from old pieces of work is equivalent to pretending the prejudices never existed), I also don't care about the change as it doesn't change anything fundamental. Same with Humba Wumba, but I also have less attachment to Tooie than if they were to say, hypothetically, change Mumbo Jumbo. Just by looking at the Nuts & Bolts design, for me personally, feels like a bad fan art version of the character, rather than an updated version, but I also have no issue if they go with the Nuts & Bolts design. Just keep that away from their moves.
All I can say is Humba Wumba is a lot less problematic than the Game & Watch situation, and potentially being a spirit, is a lot less important aspect to Banjo & Kazooie's inclusion in Smash to cause such an uproar. And if it does, there's absolutely no worries about that affecting Banjo & Kazooie in any way shape or form.