And about the Tachikoma song, i'm not sure which one you mean, but if it's the one they sing in the last episode of the 2nd gig then this is what i found.
[Link] If for whatever reason, the link decides not to work, then this is what it said.
It said that the song is called Bokura wa Minna Ikiteiru (We Are All Alive). It's a song Japanese children learn in elementary school.
As such, that might explain why it wasn’t released.
There was an attempted translation, but the original lyrics were not given.
“We all are alive.
Alive, because we laugh
we all are alive
Alive, because we are so sad.
Raise your hands and see.
Red blood running though your palm.
mimizu (a bug),okera (a kind of bugs), and amenbo swimming bug)
Everyone, we all are alive and friends.”
Tachikoma suicide song Wow. I got goosebumps while watching it again.
eek whee