Thanks for the answers to my questions, guys! Really appreciate you sharing your knowledge with me. I know nothing about these cars, but slowly learning as I stumble through.

@Maxbumpo
About question 6: is there a way to bring the idle down? Idle speed to me does not sound high, but I would not be able to determine that by ear anyway, as I have nothing to compare my idle speed to.

So, on my to-do list of a gazillion things, the two things that are top-priority right now are my flex discs (they have small cracks in them, unfortunately), and changing all the fluids. After that's done I could start driving it for small trips around town. I will still need to change the left rear-axle and put a new boot on the right one, but that can wait another month. I don't really care about messing up the left axle, as I've already decided I'm going to replace it. Currently it doesn't make noise, so it should hold for a few weeks of driving. It probably hasn't had a boot around it for a long time anyway.

I have no problems locating fluid for the brakes, differential and transmission, but the coolant might be a problem.

Here's why: I read online that this car is only supposed to take either Mercedes genuine coolant or Zerex G-05.
I don't know where to get the Mercedes coolant. The dealer is 6 hours away, and I can't order this online as fluids cannot be shipped to Alaska. Hazardous stuff is ground shipping only, and that's out of the question with most online stores and sellers.

I have located a store that sells Zerex G-05. But - and this is the problem - that stuff is 50/50 pre-mixed.
And that won't cut it here in winter. Lowest temperature at my house this year was a nippely -49 Fahrenheit (-45 Celcius) and the 50/50 premix only goes down to -34f.
In my daily driver I mixed my anti-freeze to 65/35 which gives protection to -63 Fahrenheit.

Since the Mercedes will be stored outside during winter, I need something in there that won't freeze up. To be on the safe side I need it to go to -55f at a minimum.

Any recommendation on what I can possibly use? What would you do yourself if you were to store your Mercedes in an industrial super-freezer for 6 months?
The sticker underneath the hood says it needs anti-freeze that doesn't corrode aluminum parts. That is the same as my Mazda specifies. Can I use the same (green) anti-freeze as I put in my Mazda?

If not, is there any other solution?

Fairbanks certainly has its challenges with the winter temperatures...

EDIT:
Apparently Ford uses the G-05 stuff in their cars as well, and there is a Ford dealership here in town, who might have the 100% G-05 stuff. I'm assuming they wouldn't sell cars with a 50/50 mix in it.
I'll call them on Monday (they are closed now), and see if I could possibly buy it there. In the mean time though I'm still open for suggestions...:-)