Awesome, I added the dashed lines from your links.
I had a peculiar problem with accidentals that were the result of the diatonic scale being 9 notes rather than 7. Basically, if c#' in BP is written with cis', then c#'' is written with eis'', which is enharmonically equivalent to f'', which screws up the MIDI. I devised a workaround with invisible key changes. I can write music now and have correct MIDI output, but I still have to change the names within the editor. I am miffed that Lilypond doesn't define new commands with simple substitution, so I can't just easily rename all the pitches (as far as I know, and my knowledge is in a fledgling state). But I will look through your links more on changing note names as well as on how others have made BP music.
Thanks!