Quick update--one of the admins for the ALIEN: The Illustrated Story Facebook page has clarified what's going on with the reissues, or at least how they're being remastered. All the artwork, both the original B&W and color, has been completely rescanned piece by piece from the original artists archives, with the text separate. Sounds like they're rebuilding the entire graphic novel from scratch.
I guess this means the artwork is going to definitely look much better than the original 1979 printing, especially with modern scanning and printing techniques. So looks like we're getting a definite upgrade! Hopefully they don't change the formatting too much from the original.