You can find out the full details here:What where the Sony blu rays like just the dvd features on the blu ray?
http://bluray.highdefdigest.com/4184/muppet_space.html
http://bluray.highdefdigest.com/4183/muppet_manhattan.html
Having not really seen the DVD (even though it is a blu-ray/DVD combo pack) I'm not really sure but Manhattan had some pointless Muppetisms (short footage of the muppets doing something/saying a few lines) which weren't really related to the movie at all (including one of Pepe who didn't exist at the time), and there was an interview with Jim.
Space had some outtakes, 'Shining Star' music video and just some trailers for the film.