< 1) I sometimes like to add custom transitions between two sections or styles that BIAB cannot do as easily. In this case I use what BIAB gives me and write my own transitions if necessary, or sometimes just change something in one or two BIAB tracks to make the transition logical. Probably a lot of users don’t need this.>
The BIAB Song Form Medley Maker is a tool designed to specifically do this. It's possible to create transitions up to 16 bars. BIAB transitions are user modifiable.

< 2) Song Form is a good starting point for experimentation. But it is best when you have just one style for all sections. At present when I have different styles for different sections (marked in Bar Settings) Song Form does not recognize these style differences. If A is in one style and B in another, the next A keeps the last style (B) when it comes back. It appears Song Form only copies and pastes chord names (not other things like style-change). If you mark a certain range of bars as a distinct letter, Song Form should know to copy all the attributes of that section – or better yet - to have a dialog to choose what attributes of Bar Settings to include or not.>
I tested this scenario with the MultiStyle Demo of Style- Evolve - it's a MultiStyle with 4 style changes with each style having 2 substyles and the Song Form performed the task as expected.

< 3) A problem with Medley Maker (as well as the traditional style-change in Bar Settings) is that the mixer does not display the instruments of the new style. The mixer only displays the track information for the first style, so I can't see or tweak or substitute instruments for the other style, which I should be able to do. In fact, it keeps the name of the instrument of the first style but plays the new instrument on that channel. >
BIAB has two Medley Maker programs and it appears you are referring to the Song Form Medley Maker.
The Song Form Medley Maker is a Player and not an arranger dialog window. It's a performance dialog window that plays SGU files and is not an edit dialog window. If there's a need to "see or tweak or substitute instruments for the other style, it's done in the SGU file the Medley Maker is reading from.

< 4) I assume the architecture of the mixer has only room for one main bass/drums/keys/guitars/etc.- of the first style - so it is impractical for it to keep swapping between them on the fly. Of course, with all-tracks-equal, I can manually duplicate a style by separately loading each instrument into a utility track so that they can all be seen in the mixer, and then mute or silence all the bars of each style when the other is playing, but this would be quite cumbersome and laborious, and take a lot more time than just dragging two separate songs into a DAW. >

No. That's a wrong assumption. The original Legacy Tracks of the BIAB Mixer can have up to eleven RealTracks per track. The RealTrack instruments can be directed to play alternately or have all eleven instruments play simultaneously. They can be individually volume leveled and panned. The BIAB Mixer Legacy Tracks can generate and play 77 RealTracks simultaneously.

Second, instruments duplicated from another RealStyle loaded into Utility Tracks and generated are influenced by the current style loaded into the song project and not the other style. In order to have another style's instrument play on the Utility Track with a different style, those instruments have to be generated seperately and imported as WAV files the same as you do by dragging two seperate songs into a DAW.

< 6) I'm wondering if I can have two or more different styles in Medley Maker (or just style-change in bar-settings) and could there be an automatic button to print the tracks of the new style(s) into utility tracks (and appropriately mute both styles when the other is playing)? In that case I would definitely find it useful to stay within BIAB longer. >
Yes, there can be two or more different styles in the Medley Maker. As stated earlier, the Song Form Medley Maker is a performance read dialog window so it is not restricted by the Style of different SGU files it reads. There are some limitations but as a general rule, the Style doesn't matter.

Style changes made in Bar Settings are just that, made in Bar Settings which is separate from the BIAB Mixer. Bar settings are also initiated after the BIAB algorithm has read, selected and generated the track.

< 7) If the above suggestion (6) were implemented it would solve the problem of different instruments playing on the same track when you drag and drop a file to a DAW. At present, the bass or guitar or keys track just changes patch or player on the same channel, and you have no ability to separately tweak the volume or panning, etc, which would be easy if every style change made a new set of tracks in the mixer. >

Medley Maker is an older program design and it is not optimal for these tracks to be exported to a DAW but rather to assimilate and complete complex stereo arrangements for performance from within BIAB and eliminating the need to do such arrangements in DAW. These tracks work best imported into a DAW as stems rather than tracks.

BIAB has the RealTrack Medley Maker to control different instruments playing on the same track. It appears as a sub-mixer to the selected track with controls for volume level, panning, and settings to direct instruments changes.

< 8) Yet another bug I’m sure people must have found in Medley Maker is that it does not include any other utility tracks that are saved in the file(s) that it references. I assume this will be fixed at some future date, as will some other bugs in the Medley Maker (strange transitions? etc.) >

Both Medley Maker programs have existed for many years prior to the introduction of Utility Tracks and neither program is new or in a beta version. There's nothing broken. They are rock solid as far as I can tell. I agree there will likely be enhancements and upgrades forthcoming. They have been improved in past releases.

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.