I am hearing a lot--a LOT--about how Trump can't just wholesale cut departments or agencies, which is true. His administration CAN, however, reassign, redirect, and modify how those departments and agencies are going to be run. Still I foresee a million and one lawsuits. Congress will simply refuse to cede any power.
I'll post the link when I get home, but one website is tracking all of the lawsuits against Trump and Elon right now.