I am looking forward to the results of the drive home.
it is a good time to have a qualified BMW tech, up close and personal, a fresh set of eyes, weigh in. Realizing it would take more time/$$$, consider, if you are not, not telling the tech what you have done to attempt to correct the problem and let him start from just the symptoms so the troubleshooting is from base 1.
When will you be seeing the tech?
Do you want to do anything more between now and then?