Good news, friends. I double-checked the button placement against the other pieces and it seems like he's placed the button a touch lower than the other 1 button and it's more in line with where the second button would be on a 2-button. This means I can safely add a second button above and still maintain a decent button stance. Whew. Re: the sleeve length, it's actually fine - shirt was caught in the sleeve, hence no visible cuff. Gorge, lapel width and pocket size can all be addressed in future commissions.