shows you are confusing, or at least you were confusing.Edit: Technically の is also a noun, so here we have the same thing... That's odd. Never noticed that really.
No. A nominalizer の and a pronoun の are different. Please read again the thread I linked above.There's a particle の, a nominalizer の... Well, technically, that's all of it.
Of course, since the particle の has multiple functions/meanings, and the nominalizer and pronoun are different.Now let's make something clear. When I say that the の (as in "中学生の私") is a particle and the の in "どうしたの" or "そういうのは" is a generic noun, then that doesn't mean that it ALWAYS has to have possessive or that it ALWAYS can be substituted by ANY other noun.
Not really. な is older than だ. It's from 断定の助動詞 "なり"; a classical auxiliary verb なり for assertion. な is just treated as the attributive form(連体形) of copula for convenience' sake in modern Japanese grammar.You would probably also scold me for saying that な is originally derived from だ even though I made no implication that they're the same thing and can substitute each other. That's not how it works. (It does come from だ though. I'm kinda sure of it.)
As you can see below, I pointed out the difference between them since they are different in meaning.It doesn't even seem to be too clear since, you said "the [の in the] second [sentence] can be interpreted both as a pronoun and a nominalizer."