Is “one” in the “one of the” construction a pronoun or a determiner?

They are both determiners of type 4 in the dictionary entry under your determiners link. That is both the criteria and the objects sold in auction are groups of which the specific items are members. They are similar to the examples:

One of my friends lives in Boston.

One place I'd really like to visit is Bali

I looked at the examples under your pronouns link but I can't see any which seem to be similar to me. If you can say which of the pronoun links you find confusing we can probably help to clarify the situation.