Unbeaten isn't an unfinished version, it's an alternative version with no vocals and orchestral backing, and a slightly different structure. I'm the same as ElliotTamer, I think it's a perfect way to close the album.
And I'm not sure that Nobody is a demo, as far as I know it's just an acoustic version of Somebody, minus the bridge section. It's nice but doesn't really add anything IMO.
And yeah I also completely agree with Elliot that Falling Back to Earth's placement on the album is perfect. In fact, the pacing of the album is completely bang on. I'm glad they didn't have the typical epic closer like the first two albums - as good as those songs were, it would have been getting too samey to do it again.