I thought the cuffs on his jacket indicated it to be a Braemar - a Crail having just regular cuffs, and the Argyle having that sort of funny lined '1700's' sort of thing on it. Or am I just confused.

Agreed on the sporran.

I have to go to the investiture of my friend as Grand Knight, of the Knights of Columbus tomorrow evening - so I am considering my clothing for the evening (even if I am in just a support role). I am uncertain what would be correct, and cannot pick between:
Black Braemar (no vest),
Brown tweed,
or black Crail jacket (no vest)
(all of them with solid, non-silver buttons).....

Any one have any advice?