I saw a list somewhere that included a Delta Sky Club, United Club, and a Priority Pass lounge will be included in the new terminal. I will update as soon as I find out.
Here is an article from today which talks about the vendors and food options that will be available. Much better than what is there now. They are scheduled to do an overnight move across the runway sometime in February 2019! As a local to MSY, I'm looking forward to it. I have a feeling parking will be a challenge, and the ride to the rental car facility will not be fun.