Ok, she says she can probably add the buttonholes, and she's going to search for new buttons. Handsewn buttons and buttonholes are going to raise the price though.
Can you ask her for a quote as to how much, then maybe folks could make the choice wether to have it with or without.
As you said this is never going to be Kato standards because hell, we're not paying her enough to do that.
I'd be happy with something that silhouette wise has the feel of the real deal, which is why I think the most important things to try and get right is the cut and the colour/length. The rest is all just extras.
If there's no linings then maybe she could try using a slightly thicker fabric to give it that greatcoat feel?
By the way I've ordered one of that chaps unpainted Jack heads, and I'll let you all know what I think of it when I have it in hand.