You have to remember that ATSG doesn't buy aircraft just for its own airlines. It has an aircraft leasing subsidiary. So the answer to "Who is gettiing them?" is CAM - Cargo Aircraft Management. Most of them will probably be leased to outside customers. They're doing this because they expect the pool of available 767s to start drying up, so they needed to figure out where to go next. From what I remember, they're not expecting to actually see one ready to lease until 2024.