What I find kinda interesting there is that Nintendo seemingly did care enough about Rare's DK characters that they went ahead and provided modern redesigns for most of them and even made a few new characters, for contractors like Paon, Namco and even Rare themselves to use.
For example, remember those new Kremling OCs from Barrel Blast?
An old interview with Barrel Blast's dev team reveals that they were actually created in-house by Nintendo's character team.
You also have a weird case in the form of Tiny Kong, who got redesigned into being a teenager starting with Diddy Kong Racing DS. Rare had explicitly stated in a Scribes circa 2007 that it was Nintendo's decision to do so, so it all lines up.
Some of those so called "Paon designs" are still being used to this day, like Funky, Dixie and even K. Rool in Smash Bros. Speaking of which, you'll remember that Smash Brawl and Smash 4 had trophies of certain DKC characters with modernized appearances that never appeared anywhere else.
I suppose Nintendo had made these in the event that a contractor or developer wanted to make use of them...but I guess nobody got around to.