What's the Name of That Book??? discussion

I read this (fantastic) book in the last five years,

[spoilers ahead]

This is a relatively recent book has a few equally important plot lines... the thread that ties them all together is a short script of a children's drama club play. At least one future scholar is studying the fragments of this script, trying to put it in the right order and understand it.

But the drama club, in a library or school in seattle, are presenting their script to each other on the night when a disturbed man enters the library to shoot them. He encounters the drama club teacher and eventually shoots the teacher

The second story is about a girl on what seems to be a star ship. She is alone, tended and cared for by a all knowing AI computer/caretaker (librarian?). She learns of the script fragments while isolated and is fascinated by them. The computer has been her only companion for years. She was isolated by her family when a plague developed in the star ship. She outlives all off them, but one day notices a spider in her room. She puzzle out that something is very wrong and escaped from the ship, only to find that she is not in space, but in an abandoned Lab/Facility on a desolate shore..

The third plot line is that of the shooter, who, after serving time for his killing, creates a private printing of the script of the drama club play (red leather cover) and presents it to the children who survived the shooting...

The fourth plot line (the fuzziest to me) is about a young boy who is an expert at driving a large bull in a ancient time who escapes an impending war and goes to live with a girl. Somehow he has something to do with the text that turns into the drama club script....

this is definitely garbled... but hopefully one of you good souls will recognize it...

Definitely Cloud Cuckoo Land by Anthony Doerr!

!!!!!!