| Quote #1 If I had not met the red-haired boy whose father (1) |
If the speaker had never met this boy, he wouldn't be where (and who) he is today. Our speaker didn't choose to meet this boy, he just did.
| Quote #2 and if I had written anything else at the top of the examination where it said college (10-11) |
This could go either way, but it seems like more of a choice, or free will moment. The speaker chooses a certain college and that sends his life down a certain path.
| Quote #3 […] or if the questions that day had been |
Now Merwin is mixing it up. The speaker chose the college, but not the difficulty of the questions. So there's a little mix of a fate and free will here.