I agree with you on most of what you said, but at the same time not much has been shown of the Sith Acolytes besides whats in the trailers. So when people are putting together there costumes they're is definitely some leeway. You've definitely done your homework with the close ups, one other point I would like to make is that on the robe the color is dyed or painted and not strips sewn on; which has seemed to elude everyone as well. I've used fabric paint and lightly coated my robe to give it the dark red color while maintaining it's flexibility and look.
My armor is being made by TC9948, and my mask was made by Robert at mywickedarmor.com; they both do great work. I will attach the armor to a vest much like you stated. As for the leather under the forearms, it's an unnoticeable detail so I'll stick to my black body suit and if required could have the stitched pattern put on it.
At this point I'm happy that it has become an accepted costume, even if some of the accepted ones are less then satisfactory looking. Looking forward to seeing your finished product, you're obviously going for perfection so should be great.