Jennings isnt leaving Green Bay.
They were already negotiating a contract with him. He decided to postpone talks until after the season. Unless something goes horrifically wrong with their negotiations with Clay Matthews and Aaron Rodgers and they have to franchise those guys instead, Jennings will be staying in Green Bay. Packers have a habit of locking down their receivers longer then is really necessary(Donald Driver) and of listening to Rodgers when it comes to "his" offense.
Out of all those hitting free agency, Bowe has the highest chance of actually being on the market. He has often been at odds with his teammates and management, he wasnt drafted by Pioli, and they drafted Baldwin a year ago. The fact that he was drafted in 2007(and has produced since then) and they havent made any real strides in locking him down suggests that he will be leaving.