Well, IIRC Vocaloid is a Yamaha product, so it doesn’t come as a shock that they would make an editor for Cubase. I toyed with that technology 4-5 years ago and it was a complete mess. The product was called “Diva.” It was based on Vocaloid and it supposedly allowed you to have a soprano sing anything you wanted. It was very buggy and the editing process was long and complicated. Not to mention that the editor was so bad, it looked like it was developed for Windows 3.1… Hiring a singer was WAY WAY easier and cheaper (considering that time is money…)
I hope things are better now. But I’m not going to bother trying again any soon.