Is it a noun or pronoun or something else?

Circle the nouns in the following paragraph.

For the first time in her life, Mary was seeing two boys at once. It involved extra laundry, an answering machine, and dark solo trips in taxicabs, which, in Cleveland, had to be summed by phone, but she recommended it in postcards to friends. She bought the ones² with photos of the flats, of James Garfield’s grave, or an announcement from the art museum, one¹ with a peacock-handsome angel holding up fingers and whispering, One³ boy, two boys. On the back she wrote, You feel so attended to! To think we all thought just one² might amuse, let alone fulfill. Unveil thyself! Unblacken those teeth and minds! Get more boys in your life!
— Lorrie Moore, “Two Boys”

1. Why is the one in "one with a peacock-handsome angel" a noun? 

2. In my opinion, the ones in "she bought the ones with photos of the flats" can’t be a noun because it is a pronoun. Also, the one in "to think we all thought just one might amuse" means indefinite or nonspecific people; therefore, it is not a noun, but a pronoun. Is my reasoning correct?

3. Is the one in "One boy, two boys" not a noun because it is a determiner as in one, two, three, many?