First, it's referred to on the site I found it on as just a "highwayman coat." This doesn't sound like it'd be accurate, but I'm not sure-- what were these styles of jackets called in their period? Dusters? Surely highwaymen weren't the only people who wore them.
Secondly, the high double collar- Is there an actual term for that piece (or for that matter, any kind of thick, high collar that sits up high like that). I'm assuming that whole shoulder mantle + collar piece was removable, but I can't find anything that explains what purpose it served. Am I right in thinking weather?
Basically, anyone who's fashion history savvy, tell me all about that jacket (preferably from the first photo, not the Vash reference).
All I can find are modern "double collared" shirts on google, which is pretty far from what I'm thinking of.