Are there any REs or sound libraries available for REs that are similar to packages like Realivox or Vocaloid? Like good playable, manipulable vocal samples?
https://shop.propellerheads.se/product/tone-mutation-vocals/
This is an interesting idea I suppose, but the demo isn't terribly impressive. It's basically vocal formanting for whatever sounds you want to run through it. Not really a vocal sound generator.
These may work for you. I'm coming at this from a dance music perspective so your milage may definitely vary.