I'd hold off on the working button holes man. The examples I've seen on this forum, although probably biased, when it's been altered is usually a real horror show. RLBL is a nice, slim, fully canvassed suit so you should enjoy it as is. Getting better buttons is not a problem though.
Guess who installs working buttonholes on RLBL for $120 all-in ($15 per button-hole)? The Ralph Lauren Mansion in-house tailor. I can't imagine them screwing their own stuff up, particularly when they do that ALL day for their Purple Label suits.