Looks good, and as has been previously suggested:

1) wear a three button vest (low cut, and you can buy/rent one from a tux shop or get it from the folks who sold your pal the mess jacket).

2) the kilt should reach to the top of the knee (that's military regs) and the hose should be two inches below the knee (again military regs).

[Since your pal is wearing a military uniform he should try to adhere to mil regs.]

I'd skip the sgian duhb because (a) it might cause problems with the school, and (b) because it will keep sliding down your hose while dancing.

You and your buddy have a great time (and let's see some pics!).