I believe I recall that the brigade commander [Phifer] was known as a stickler for military precision, maybe even to the point of being labeled a martinet by some of the wild western dismounted cavalry troopers in his brigade.

I think you've got him pegged right. Somewhere around here I think I've got some correspondence dating from his days as a cavalry battalion commander. As I recall, it deals with an arrest and court-martial of one or more officers for "attempted mutiny" (actually, disobedience of orders). I also have some correspondence dealing with his alleged "high-handed" treatment of the two Louisiana companies in his battalion. Includes correspondence with a Louisiana congressman.