Comma after nonrestrictive adverbial (dependent) clause at the end of the sentence

Is there a majority-accepted rule (or, at least, majority position) around restrictive / nonrestrictive adverbial clauses, or is this merely a stylistic / subjective preference?

All punctuation rules are stylistic, and most manuals of style recognize that rules have exceptions and are flexible enough to accommodate an author's judgment. Thus you may argue just about anything you wish. But bear in mind that you may mislead your readers. When you write nonrestrictively

I went to the airport to pick up my sister, Ellen.

your readers will infer nothing about additional siblings. On the other hand, when you write restrictively

I went to the airport to pick up my sister Ellen.

your readers will infer that you have at least one other sister not named Ellen.

This doesn't matter much when the semantics of the sentence states or implies the information.

In the sentence

I will see you at 9:35 pm after the party has finished.

the adverbial clause is nonrestrictive because the clock time has already defined the time of the assignation. If you leave out the comma, nobody will assume that you mean any other 9:35P, multiples of 24 hours before or after.

Likewise

The plane landed after a 10-hour flight at 10 am.

will likely be interpreted as

The plane landed at 10 am after a 10-hour flight.

and that if you had another 10-hour flight in mind, one that landed at some other time, your readers will assume that you would have mentioned that.

Although you're entitled to your own style, be aware that by banishing the nonrestrictive comma, you give up some concision. As you pointed out, in the sentence

His faxed response came this morning after the decision had been made.

the clause "after the decision has been made" may be restrictive, i.e., it may define the time of the morning, distinguishing the time of the fax's arrival from other events of that morning, as in

His faxed response came this morning after the decision had been made but before the press had been informed.

Or it may be nonrestrictive, in the case that nothing else if note happened that morning:

His faxed response came this morning, after the decision had been made.

A rational stylistic argument may be made that it is better not to rely on so slight a mark as the comma to convey important information. In that case you may have to add words or shift them (e.g., by making the nonrestrictive clause an introductory one). If you're not writing for yourself, however, you may writing for an editor (or grader) who can impose a manual of style upon you.