Answer

It seems to me that yes (it is permitted, and therefore also obligatory). First, because I’m not sure he really has the status of an important person, though maybe he does. And second, because nowadays there is no issue with reclining in front of an important person anyway (since reclining has lost its social significance). Everyone reclines in front of everyone.
No permission is needed. The commander won’t understand what you want from him.
The Rema wrote that nowadays women also recline, because they are considered important. It also seems that way to me, humble as I am, on logical grounds.