Honestly, try opening the file in Realband instead. Most of what you are needing/requesting is available and already implemented in RB. You may have a small learning curve, but you may also find joy quickly.

Your workflow sounds like it would benefit from knowing 'when' to switch to RB. Start in BiaB, then switch to RB for additional features. They are different, but many BiaB features carry over to RB yet RB gives you many other options.
Start a new project in BiaB, then once happy with the basic arrangement, and you need to start surgically changing things try moving to RB

Freezing a track? Not needed in RB; just cut what you don't want and generate new parts using the same or different style .. on another track (48 available instead of 8 or 10) or the same one. You can even generate multiple takes for only a given section, and cut/paste to hearts desire.

Transposing the whole song, or a section, is easy in RB, including audio ..

It's different than BiaB and more powerful in many ways. Not as quick as BiaB sometimes, but more exacting when you need it. Learn to use both, like I said; your workflow seems to fit the ideal RB user (in conjunction with BiaB).

You likely already own it (included with most BiaB recent purchases). You may be pleasantly surprised at what you already have the ability to do.

I do not work here, but the benefits are still awesome
Make your sound your own!