Brand new to this site. Been a die-hard follower since 1985 of the band. There seems to be much debate about what the opening song could be. Think back to Popmart, nobody would have thought Mofo would open, much less every show. Also, 360 tour, nobody would have thought Breathe would open. Even Vertigo tour, everyone naturally thought Vertigo would open, then COBL took the slot.
If you think of an intermission being involved in this tour, this means that they really need 2 good openers, one for each set. I think Invisible would work best to open the 2nd set to get the crowd moving after the intermission. I know many hate it, but I really feel Cedarwood Road will be the opener. It's where Bono's life started, the band started, his songwriting, where he learned to play guitar, etc. it logically fits to be the song where the show starts. Then they could launch into something from Boy (Follow, Electric Co, Out of Control). Then it could progress with California, Desire, Volcano.
They are a band that likes to tell an entire story from beginning to end, with high points and low points in between for their setlist. They got away from this somewhat during the 360 tour and at times I think it suffered a bit.