I know nothing about sewing, so forgive me if this is a dumb comment...
I wonder if it would be possible to have interchangeable buttons? It sure would be convenient if you could just switch buttons. On the jacket, the buttons don't have to function as a "button", so there is no tugging or pulling on the buttons. This might not work on the waistcoat, and so perhaps one could have two waistcoats - one with silver dress buttons and one with informal buttons. OK you tailors out there - is this possible?