For about 5 years I've been using BIAB to make backing tracks to perform with.
For my instrumental guitar gigs I usually create tracks that use bass,drums and one (sometimes 2) chording instruments other than guitar (piano, b3, rhodes, accordion,vibes, etc)
I take the wav files from biab and do the rest of the work in logic
I'm very satisfied with these results.
Until now.

I want to create bass only and bass & drums only arrangements of these same songs.
My plan is to perform as a guitar/bass live duet using no tracks. Perhaps one day a live trio.

So, I want some stripped down versions to allow me to evolve and practice my new guitar parts. Turns out I too must evolve to play in a duo or trio.

I'm finding that sometimes the BIAB bass part I've selected for the 4-5 part ensemble doesn't work well (or at all) to these more sparse arrangements. Sometimes not enough notes, sometimes too much syncopation, etc.

I'm spending a lot more time creating utility tracks of bass lines and testing those wav's in BIAB and my Logic project. I'm already looking for simpler bass lines and setting the simple arrangements in BIAB. I haven't found those to be game changers
Its pretty time consuming and at times frustrating.

If anyone can provide some insight I would appreciate it.

Thanks

Other than writing your own lines with MIDI all I can suggest is borrowing a bass and recording your own.
I'm not keen on BIAB bass for the most part but then I track my own parts 99% of the time.