Some Vicarious Visions resumes on LinkedIn suggest they are full remakes.
You wouldn't need to do multiple style concepts and mockup the UI if it was a direct port. Maybe redraw the art at higher res, but this seems to imply a totally new HUD and menus.
Oho, I knew there were implications, but I didn't realize they were doing concepts and UI stuff. This is really promising. Still, I'd rather not get my hopes up, just to be safe, haha.