I believe some of the leading boiled wool garments on the market today are still made, then shrunk/boiled. You shouldn't have trouble finding green wool fabric if you are ready to boil your own. As for buttonholes, I can't speak to their authenticity, but a proper handmade buttonhole will withstand just about anything. I suspect a deerskin-bound one would also wear quite nicely, though. Sewing it on in a period-authentic fashion would be a chore. I hope you have had your 18th century Wheaties.