See about mini implants to keep them in, with confidence! Very pricey, but only a couple fo bottom.4500$ or so! Canadian!
For some, it takes time to learn how to do things in them, including talking, so I'm assuming there would be a chance of needing time to learn how to sing in them.
Only on Tuesday.
My mother got full dentures 2 years ago, and she sings in the church choir every Sunday. She has not complained about it.
I don't have them, but my brother in law does. He says as long as they fit right he can do everything.