You can set it up to have the subdomain completely hidden behind the reverse proxy, if you do so, google won't notice any difference. If the subdomain is in the same local network you can just disconnect it from the internet, if you can't you can still set the subdomain robots.txt to reject crawlers. Just be carefull to do not serve the robots txt under the subfolder.

What's the attribution rules you set up in FB business manager? google analytics counts only last click as a click, by default facebook counts any click as a click,

if your site is on http and the user is browsing facebook on https (which most likely is) the referrer header is lost on the click, and you will see the visit as coming from direct traffic, you can fix that just adding analytics tracking parameters to the url you publish on facebook

I regret I have not understood the question, what do you mean with "unique urls"? Can you post a link to show that website?

Yes it may be beneficial to have more than 1 article with link from the same domain.

As a rule of thumb, do it only if the articles on that domain are getting some internal juice.

And do it only with article targeting different keywords, and linking to different pages of your website.

Check webserver log files, or log visits (ip address, user agent, __utma, __utmz, possibly browser fingerprint, etc...)

Analyzing those you can easily find out if the traffic is from scraping bot or humans.

99% of internet users are aware of only two TLD, their homeland ccTLD and .com

If you use .eu most of people who actually type the domain will either try their ccTLD extension or .com, so if you own the .com too you should redirect the .com to the .eu, but why do so? If you own the .com just use the .com, if you don't, change domain and use one with .com

That's a common cheating technique (Product schema in place of Organization), so far I never saw google spotting it.

I would expect product pages to have AggregateRating markup for that specific product. Not for the organization. Google is not going to show that rating anyway, so why put it there?

Keep in mind, you want star rating to appear in SERP because will improve CTR.

To have star rating appear in SERP you need markup and a user query matching the target of the rating.

Let's assume you sell vegetables and your organization name is "Veggie Inc".

Would you expect the product page for "Early Girl Tomato" to show up in SERP when people search for "Veggie Inc."? Unlikely. So if you add organization aggregate rating markup on that page no one will see that.

Do you think the star rating will appear on "Early Girl Tomato" page for other queries? No way.

Best practice is Organization AggregateRating on 1 page, usually the homepage, which people will likely search for using your brand as query, a query which will match your Organization name...

Hope I was clear.

In addition to all the good things said by others. Be careful about the following:

1. if you add AggregateRating markup for "ACME Inc." it will probably (as you may know google takes into account a variety of factors, not just the markup presence) show up, when people are querying for "ACME Inc.", but if your organization is "Potato and Tomato Inc.", and the user query is "Potato Tomato" won't show up.
2. don't confuse google guidelines for "Reviews" with "AggregateRating", you may have multiple reviews on the same page all nicely marked up, it's perfectly fine for google, but you may have only one AggregateRating markup per page.

Of course you can have AggregateRating plus additional schema.org markup on the same page, like reviews, but only one AggregateRating markup.

First, I really think you are underestimating the importance of on-page optimization. If you read that backlinks are all that it matters, it's true, but given that the html code is not a mess. And even so, when comparing two websites with a similar backlink profile, the more on-page optimized wins.

Second, let's take hotme.ca, for which keywords are you analyzing its ranking?