I am mostly wondering if proper nouns exhibit distributional and/or morphological peculiarities that set them apart from pronouns from a broad typological perspective.
A distinction between common and proper nouns is a semantic one, not grammatical. There is nothing special in a morphology of proper nouns, as any common noun can become a proper noun. In fact most proper nouns were at some point common. e.g. brand names like Windows, surnames like Smith, etc.
Pronoun is not a type of noun. It's a word, typically shorter one, that may substitute a noun or a noun-phrase in a sentence. e.g. you, their, which.
They aren't easily comparable with each other.