Seats at the front of the plane are given to those customers with a fused or immobile leg, service animal, or who require the use of an aisle chair
Printable mobility device handling form to attach to your device: https://www.delta.com/content/dam/delta-www/pdfs/mobility-device-handling-form-v8-official.pdf; also, "Will my device fit?" feature, where you can input your device measurements: https://www.delta.com/us/en/accessible-travel-services/wheelchair-services
Profiles of Delta's fleet show which planes have accessible restrooms and where they are located: https://www.delta.com/us/en/aircraft/overview
Contact Special Assistance for any kind of information. t 404-209-3434