There’s been a few retired General officers to head the VA, but I’ve never heard of an active duty general/flag officer heading the VA. Sounds strange to me, but Trump I guess can nominate who he feels like nominating. The leaker McMaster who Trump fired as NSA I guarantee will get a 4th star for the “outstanding” job he did in the White House. What a joke.
McMaster is retiring, and he'll be retiring as a three star. I believe that you have to fill a four star role for a minimum period of time to retire at that rank.