I'm going to take a wild shot at a response before the people who actually know what they are talking about chime in.

You're onto a clue when you mention the Soloist. BIAB of course, has both virtual keyboards and fretboards which show you what the soloist is playing.

By regenerating the song...you will get at least slightly differnt solo runs every time and I would GUESS that if you change Styles...within the same genre...you would probably get quite different solos.

And you can SLOW the tempo down to a crawl to make it easier to see and follow along with the scales/modes the Soloist is playing.

But I don't know of a way to FORCE the Soloist to play any particular scales/modes...but that doesn't mean there isn't one.

Best,

Jim