Sorry, I was confusing with the Superman blue box liner notes (which mentions a 6-women choir for the Krypton sequences). My bad! However, listening to that cue, it's likely Williams used a very small women ensemble for the Cloud City cue as well. It's definitely not a synthesized one.
I think it's just a perspective shift. The original version plays Bilbo, and his house being turned upside down. (the piece that plays here is actually an inversion of the rural setting of the Shire theme - clever!) The rescore focuses on the dwarfs' merry-making. I like both equally.