Funding for the $2.1-billion Purple Line light rail project is becoming less certain as time passes, and key members of the project staff have quit in the past month. Most critically they include Henry Kay, the Maryland Transit Administration’s executive director for transit development and delivery, Ronald L. Barnes, Senior Deputy Administrator and Chief Operating Officer, and Jodie Misiak, MTA’s manager of innovative finance. DBFOM bids from four shortlisted teams that were competing for the Purple Line P3 are due Nov. 17.