Come on, they're bound to release DK64 eventually, they did on Wii U VC and they’ve made a big deal about the fact that they’re releasing Rare titles that they haven’t rereleased before due to the deal with Microsoft, like Jet Force Gemini, Blast Corps and freakin’ GoldenEye. It’s going to happen at some point, and it will be a big fireworks-type event that will make Nintendo Direct headlines when it happens… and it probably won’t get removed from sale like it did on the Wii U!
imo the fact that they’re releasing obscure stuff that they haven’t rereleased before on VC on NSO is overall a good thing. There is a definite stench of “this is something we could actually license” to adding random third-party stuff like this, but compared to the “most of the notable first-party N64 games” lineup the Wii and Wii U had, the fact that its library is going to be more than double than both of those by… possibly even the end of this year, and the fact that I can just pick something up and go “hmm, haven’t tried this before” is one of the biggest benefits of the NSO approach imo.
Now Ogre Battle 64? That’s probably not coming back again due to Square Enix’s NSO allergy. Bomberman? Up in the air at this point. DK64 and Diddy Kong Racing? Yeah, they’re probably happening.