Besides government officials and foreign signatories, the largest section is indeed about clergy.
Note that this is super formal. In most business you can get by with Dr. and Prof., nothing else.
"Eure Spektabilität" and "Eure Magnifizenz" for the "Dekan" (dean) and "Rektor" (president/chancellor), respectively, of a university. I wish to meet one, just to use that term.
"Wenn diese Deutschen einen Bahnhof stürmen wollen, kaufen die sich erst eine Bahnsteigkarte!" - Lenin (probably not really though.)
(Disclaimer: we live in Japan and he lived in Switzerland before)
Having a PhD has never been an issue, usually an advantage, often neutral.
As for the salary - this is normal. You apply to an engineering position so your experience in engineering positions/education counts. A PhD is not a hinder but not a huge booster either. This is not different from other countries, except for Germany and to some extend Poland and Italy.
Please note that France is extremely unique when it comes to engineering schools. Our pride in prépas and then top schools does not count at all abroad. You finished Polytechnique? OK, that's an engineering school in the top 100-400 of international schools.
Well, it's common in the US too, from what I've read. Tech companies (in IT at least) don't particularly care for PhDs...
I worked in IT for two large US companies (from mid-90's to end-00's) and the first job my PhD was not a particular asset (but nothing wrong with that) and it helped for the second one.
No, but it is often perceived as a sign that "let's skip this person, they are too researchy, older than a college graduate, and likely to ask for more too".
Coming from a country (Portugal) where having an Engineering degree still has a similar connotation and there are still some that make the point to be called Eng. SoAndSo, specially on smaller towns and villages, it was kind of ironic to find a society where it is taken to the next level.