Exporting midi is relatively easy... Opening midi is still problematic in some instances (most for me...)
If "markers" are present in the file (Midi), BIAB messes up sync between imported midi (on melody channel) and real tracks. Reported the problem over 2 month ago in detail with examples...So far have not heard back from the team.

There is a manual workaround, but not a very healthy one. Which requires opening Midi file in another program and getting rid of markers manually on each track and re-saving MIDI. I suspect that BIAB takes a marker or program change of the imported file and interprets it as a starting "note" and syncs start time to that marker.

Still patiently waiting for resolution/fix... and wondering if anybody else have same issues opening midi files and adding Realtrack in BIAB.