Hi Mark,
Re your BIAB questions:

(a) How much can you change the melody.
The things that are easy to change in BIAB are the chord names, the melody and the the soloist sections. The melody and soloist section can be edited within BIAB by a number of methods:
- by click and dragging the notes
- by adding new notes in a similiar way to Composer
- by editing the Midi events list.

BIAB has graphical ways to edit the note duration and loudness (by click and drag). Its all pretty easy.

(b) About changing the generated Band performances - well that's a different story. Because BIAB generates the band accompaniment from its style details, all the notes are generated from those fixed styles. But you can change the styles if you know what you are doing. Its simple to change, but its not simple to get a good result. So in reality for normal mortals changing the generated accompinment is not a goes.

(c) However, BIAB does have a automatic style generation where you can play the midi file into BIAB and it will generate the style from the music. I have used this on at least one occasion and it did a great job.

Not too sure if this answers the questions - if not please fire a few more.

Cheers ... Clyde