I can't tell you the Union general responsible for the directive that made Arlington into a cemetery, but I do know I have heard/read that it was a delibert act done so the Lees would not be able to return to the property. Whether myth or fact, I've also heard some of the items removed (looted) from Arlington were inherited by the Lee (Custis ) family from George and Martha Washington. (A Custis was step-son of George Washington.) It was a long time before the Lee family ever received any payment for the confiscation of their land. I think some of the Washington heirlooms might have been restored to them. Lee is buried in the chapel at Washington & Lee University, Lexington, VA. The tomb is very impressive and there is a nice museum in the lower level. It is worth visiting if you have an interest in the Lees or his part in Civil War history. (The museum is primarily about the Lee family. ) Lee's horse Traveller is buried outside the chapel. When I was there in July, someone had left carrots on his grave.:)