TIWYCRMN is definitely about the band/Bono.
The old man is Bob.
They signed up - not for the army but for the band. It's the moment when they became totally committed to this life.
The double decker bus into College Square is how they saw The Clash for the first time, and that was it, they/he were like "this is what we/I want to do."
SLABT I assume was like Raised by Wolves, things happening as they grew up, possibly affecting people they knew, but certainly affecting the fabric of society.