LOL, The Sun, The Moon and The Stars was originally done for the POP sessions. They worked on it again for ATYCLB but it again didnt make the cut obviously. The bit at the end of Discotheque is not this song. They thought they were going to release it as a B side or on a soundtrack but changed their mind because they thought it might go on a new album down the road. Its a mid tempo song with some piano (at least originally it was).
Other songs worked on during POP were as mentioned Novelty Act (which is NOT Big Girls Are Best), Hymn To The Universe and Super City Mania. These songs have not turned up so far in any form on any U2 album. Its also possible that some of the lyrical ideas may surface on new tracks but the music to these hasnt and I dont think it is on the upcoming album. Remember the version of Wake Up Dead Man that made it out is NOTHING like the demos using the same line from the Achtung Baby and Beach sessions. I'm wondering whether Bright Lights, Big City may have some of Super City Mania in it, probebly only lyrically though. I'm surprised that Origin Of Species which was completed during the ATYCLB sessions is not on the new album. Unless they changed the title and lyric to it. Should be interesting to see. Then again, some of these songs may not turn up until the fabled box set Edge has mentioned when U2 are done.