Been using BIAB to create backing tracks for a few years now.
The tracks I've made are pro quality, use both for recording and performing
I produce .wav files from biab and mix/automation/master in a DAW (logic).

What other software products do people use to replaces existing BIAB parts. Equally important, which part seems "easiest" to replace - drums, bass, keys, guitar?

I've messed a little replacing BIAB drummer with Logic Drummer.
That worked ok. If BIAB had the ability to mix drums I would prefer that.

Is it pretty easy to take something like ezdrummer (for example) to gen up a drum part, then drop it in on a bunch of BIAB real tracks and come up with something that sounds like a band?

For example How much experimenting is required to get an ez drummer funk groove to lay in over some biab real tracks (bass, keys, etc) created in a biab funk style.

Will it really be that much better than and all BIAB version with real tracks and its styles.

Is there a reason to start with one voice (drums, bass, keys) over the other.

I used toontrack ezdrummer above merely as an example. I know there are other players in this game. I don't own any of this stuff but black friday is around the corner and I have a little spending money.

Hope this makes some sense.

biab2023(Mac)
Logic Pro X