If you consider how Nintendo characters tend to hop around each others' worlds, it makes sense how Rare's Banjo-Kazooie exists in the same world as Nintendo's Super Mario Bros. Banjo appeared in the Nintendo 64 version of Diddy Kong Racing (back when the two companies were best of business buddies) who, of course, co-starred with Donkey Kong Country's Diddy Kong. Kong co-starred with Donkey Kong in DKC, and he bumps into Mario all of the time in the Mario vs Donkey Kong series which, and you know where I'm going with this, stars Mario himself. This transitive property gets us to a place where Banjo and Kazooie may have visited Princess Peach's castle at some point in time, and thanks to ROM hacking, we get to see that encounter. Luke Ford is working to transplant Super Mario 64's levels into Banjo-Kazooie. The hack doesn't seem to be publicly available and this video is from 2016, but it delighted me so much that I had to share it. It's strange to see the bear and bird duo wandering around Whomp's Fortress and the castle gardens, but they're an interesting fit and I would be interested in playing through the entire game with them just for the novelty factor.