Graduation ceremony and colors, need some advice...

[Carlo]

I would still go for a white shirt (I had my black-on-black-on-black phase and am happy that it is over).
You might consider a blue three button waistcoat (buyakilt does offer one in navy blue) obviously it's gonna cost something but it would be a possibility to show some blue and still be in traditional black bow tie and white shirt.

[McMurdo]

I would wear a white shirt and black self tie bow tie. If you do not know how to tie a bow tie do learn it make a difference in how the outfit looks. Here is a video that can help if you need it:
http://youtu.be/VJv4Qh7zR3E
I think the black shirt would just be too much you need some break from the black or your entire outfit will in essence disappear. As for the hose and flashes I`d say wear the black hose if you`d like but I would suggest blue flashes or better yet garter ties, they are in my experience far more comfortable than flashes. You can find blue flashes here:
http://www.scottishkilthose.com/garter_ties.html
Another thought if you have the money and time for it, as it seems to me that your outfit is crying out for some colour, would be a pair of diced hose in black and blue here is where I got my diced hose, it is an expense but it is well worth it.
http://kiltshop.scottishtartans.org/custom_diced.html