Separated (nonrestrictive) relative clauses

This question concerns relative clauses describing the subject noun phrase but separated from it by the predicate.

I first took notice of this phenomenon with Javert’s Suicide song in Les Misérables:

And must I now begin to doubt,
Who never doubted all these years?

This formation struck me as odd and it stuck with me until I just came across a similar usage in the trial of Charles I (Salmon 1719):

That is, in your Apprehension; we are satisfied that are your Judges.

This question brings up a similar sentence from a draft master’s thesis:

In this chapter, the fundamental physiological principles will be presented that underlie the mathematical models and simulations of the subsequent chapters.

This example, while perhaps not the best style, sounds much more acceptable and normal to my ears. Is the difference that the relative clause in this example is restrictive, as opposed to the nonrestrictive clauses in the first two examples?

Another question asks about the acceptability of a sentence using an nonrestrictive relative clause in this manner:

It is a fault to expect Emily to be a good teacher who doesn’t like children.

I and the answerer agree that this usage is unacceptable. Describing the reason why, the answerer explicitly states that this usage is ungrammatical with nonrestrictive clauses:

Nonrestrictive clauses occur next to the NP they go with (they are not modifiers). Your last example violates this rule, so it is ungrammatical.

And so we are back to my two initial examples. In present-day English, this formation is as odd as I think it is, isn’t it? Then, is this an instance of diachronic change? Did this (nonrestrictive) usage used to be common (or at least more acceptable) and now has become odd? (The Les Mis example isn’t that old though.) Does restrictive vs nonrestrictive factor into this as it seems? What’s going on here? I need your help, who have become confused by this 😉