Falcons .... meh.
Coca-Cola Museum and Aquarium are next to each other near Centennial Olympic Park.
Also College Football Hall of Fame is in same area.
https://www.cfbhall.com/
Definitely do the Delta Museum on the way back to the airport. Plan at least 1 hour there. Take an Uber from there to International Terminal to complete your trip.
That will save you a lot of time over returning to main terminal (where the MARTA station is).