Learn English – the structure “like for somebody to do something”

1. Such does indeed act as a pronoun, and its antecedent is indeed young men of four thousand a year.

2. Anaphora—the co-referential relationship between a pronoun and its antecedent— does not to my mind imply that the antecedent is present in the ‘deep structure’ of the utterance in which the pronoun is employed. There may be grammars which represent a pronoun-in-use as a ‘reduction’ of its antecedent, taken to be ‘present’ in a governing ‘deep structure’. This sort of analysis seems to me to contradict the facts of utterance and interpretation, and to be in consequence of very little value to the users of language, however sophisticated. Moreover, it sets the linguist on a slippery slope toward a philosophical monism in which the ultimate ‘deep structure’ is the entire language—and possibly also an experienced universe taken to be coterminous if not indeed identical with the language.

3. It is impossible to say that one or the other of these expressions is always preferable to the other, without regard to context; but it seems to me that of great wealth is not a ‘reduction’ but the ‘base’ form, and that the explicit relative who is of great wealth is an expansion of it which might be elicited in unusual circumstances.

I am not competent to address the further issues raised in your third question.

Songs sometimes hearken back to older ballads, and so we encounter in songs syntax that is a little archaic, different than we would use in contemporary conversation. These are not "grammatical errors" but stylistic features.

Compare the timeline here, for example: