Mike, you sound like a far more competent version of me:)

I like BIAB because it suits my style of writing. I always begin with a melody in my head and it's usually pretty much fully formed, with at least some of the lyrics. Then I go to my keyboard and work out the chord progression, before I ever go near a mic or a computer. Then BIAB is a bit like having a band that you go to and say, "Hey guys, I've got this great idea for a song. It goes like this."

I have never used a BIAB solo. I always create instrumental solos (sax, fiddle, harmonica, cello, etc.) with real or virtual instruments and lay them over the BIAB background. I'm interested that you have had success with the BIAB solos. Whatever you're doing sounds great, so maybe I need to investigate this further.

I only discovered Melodyne recently. I tend to use it sparingly, because I feel it can suck the life out of a vocal, if you're not careful. Not that it necessarily creates that awful autotune effect, but that it seems to kind of flatten things sometimes, especially as a lot of the stuff I do depends on having a warm, conversational tone. I think it's great for conventional pop songs, where you're not really listening too closely to the singer. Your approach of only using it on individual notes probably eliminates the problem I'm talking about. When I use it, I do use the macros, but I choose a relatively low percentage correction to get rid of the real bum notes without imposing an unrealistic perfection.

I use Mixcraft as my DAW, and the Pro version comes with the basic version of Melodyne integrated as part of the DAW. It's quite an economical way to get Melodyne, if you don't need the upscale features.