grammar - restrictive relative pronoun clause and antecedent

The Plaintiff claims that the Defendant, MICHAEL DOE, owed a duty to the Plaintiff, which duty was breached by the said Defendant, the particulars of which breach are as follows:
(a) driving without due care and attention or without reasonable consideration for other persons using the highway;
(b) failing to keep a proper lookout or any lookout at all; . . .

I thought it should be corrected as

The Plaintiff claims that the Defendant, MICHAEL DOE, owed a duty to the Plaintiff which was breached by the said Defendant, the particulars of which are as follows: . . .

There are 2 relative pronouns (which) in the original sentence.

The antecedent of the first which: "a duty"
The antecedent of the second which: the former clauses—the defendant owed the plaintiff a duty which was breached by him

1. Shouldn’t the first which have a comma before itself because the clause is a restrictive clause modifying “a duty”? Or is it ok to have a comma because the antecedent (“a duty”) is away from the relative pronoun (“which”)?





2. Someone told me that "duty" in "which duty was breached" is just added for emphasis. Is it grammatically accepted to add a word of the antecedent after the relative pronoun for emphasis?




3. Regarding Question 2, is “breach” also added for emphasis or to prevent the reader from misreading it? For example, without “breach” a reader can think the antecedent of the second which is the whole former clauses—the plaintiff claims that the defendant owed a duty which was breached by him. There is no word “breach” as a noun (except the only one in the relative pronoun clause), but only the past participle “breached”. If it’s ok to add a word after the relative pronoun for helping the reader or for emphasis, does the word to be added not have to be exactly the same word that has already been said?