I forgot to add the 'lol' to my previous post. I was kidding.
I would typically use the same thing I would use on a male singer, which is; whatever the performance needs to make it work within the context. It is never none. But some singers do not need much. And the song has just as much to do with what is needed, as the character of the voice. I myself have no template for what works. Decisions are made based on what is given.