The Hollywood Reporter broke word yesterday that Murray had been spotted on the set of the new film with a later report at Birth Movies Death bringing specifics on his character, stating that there is a role in the script specifically written for Murray to play a professional debunker of the supernatural.
So, there you have it. No Venkman in the new Ghostbusters but there will be some Murray, apparently. You have to figure that Dan Aykroyd is out there sulking about this somewhere.