Grand Forks AFB used to be an Air Mobility Command (AMC) base but has since transitioned to Air Combat Command (ACC) and is home to the 319 Recon Wing. They also have KC-135s aerial refueling tankers (which was the host Wing under AMC back in the day). That race track pattern in your first image is a refueling track. Most likely doing currency training for aerial refueling for night ops. The drone activity you see is from the 319 RW.
https://en.wikipedia.org/wiki/Grand_Forks_Air_Force_Base