Thank you for this information.
Assuming I have a long enough layover time after arriving in Concourse E, wouldn't it be possible to go into the line with no connections, go through immigration/customs that way, leave the sterile area with my checked bag, and then recheck the bag with Delta ticket counter and go back through security for my connecting flight?
Not if you have a checked bag. The checked bags for connecting passengers are sent to E not F. I don't think DL will let you "short check" a bag to only ATL if you're connecting unless you have a very long connection there.
Depending on the time you arrive, F might not have open TSA SkyPriorty or PreCheck lines. You can take a bus to the main terminal and do security there, but service isn't very frequent and this can be a hassle.