If the releases are real, I don't think they have time or budget to implement completely new animations with facial features and such, so if that can't be up to Odyssey level, I'd rather they go with some sort of low-poly stylisation.
Like, have the graphics seem like what people remember, but in reality things like sprite trees are real models, and textures aren't so low that you can count the pixels, but also aren't trying to be anything "realistic".
edit: That's if each game is going to be full priced. If it's 64, Sunshine, Galaxy, etc in one package, simply upping the res with new UI elements is fine.