Yes. BIAB can do change the soloist for the next chorus. Several methods.

Here's one:

Assume your song contains the default three 32 bar chorus's. Regardless, this method works with any number of chorus's, including a single chorus song.

Open Bar Settings
At the top of the Bar Settings Window, open the "All Choruses" Button
Select the Chorus number that you want to change Soloist instrument
For instance using the Three Chorus default example, Choose Chorus #2
Then;
Assuming you want the entire Chorus #2 to play all 32 bars of the new soloist instrument, Select bar 1 in the Bar# Box in the upper right corner of the window

Select the RealTracks Radio Button
Select the Track that you want to change the RealTrack Soloist instrument
Highlight the RealTracks to... Box (small down arrow to the far right of the box)
From the RealTrack Instrument list, select a new Soloist Instrument
Click on OK Button to exit to the RealTrack Changes Window
Click on OK Button to exit RealTrack Changes Window
Click on OK Button to exit the Bar Settings Window

Repeat the process to change additional soloist instruments to other Choruses

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.