I have to say I was rather disappointed in the film. Aside from the anachronism of showing the Corps leaving from the Jackson Arch side of Old Barracks rather than Washington Arch, which was actually there in 1861, I just find it hard to believe that Jackson, Lee and the various other people portrayed in the film were always so grave and deliberate, that they spoke so pompously. I know the 19th century was a more formal time, but the filmwriters seem to have taken the formality of written prose, and assumed it represented contermporary speech as closely as the dialog in a trashy novel representes modern speech.
My own bet is that the way Cadets talked in 1861 was not a whole lot different from the way Cadets talk today, or did anywhere in between (as in whenever the Old Corps starts for you). And, I would bet that the atmosphere in a division, corps or army CP wasn't much different than it is today, allowing for the differences in information technology available to the commander.
Yours in the bonds....
There was a certain formality involved at the general office level and I forget which of Lee's generals had a rather nasty habit of swearing, but it is mentioned in the book that Lee often let this person's remarks pass without comment as to the vulgarity. However, I am sure you are correct about the VMI cadet vocabulary. After all, the military is the military and grousing in the ranks is part of the program.