The USAF report into this crash has now been published. The summary conclusion is
"The board president found, by a preponderance of the evidence, the cause of the mishap was MP1’s improper application of left rudder, which resulted in a subsequent skid below three-engine minimum controllable airspeed, a left-wing stall, and the MA’s departure from controlled flight. Additionally, the board president found, by a preponderance of the evidence, the MC’s failure to adequately prepare for emergency actions, the MC’s failure to reject the takeoff, the MC’s failure to properly execute appropriate after takeoff and engine shutdown checklists and procedures, and the Mishap Maintainers’ failure to properly diagnose and repair engine number one substantially contributed to the mishap."
https://media.defense.gov/2018/Nov/0...E%20REPORT.PDF