Certified copies (beglaubigte Kopien) should be more than enough. Since they are not German documents, you have to let an attorney/notary (Notar) do them for you. IIRC, the fees are set officially, so it should cost the same wherever you go.
You know, I was writing a rant/explanation about DVB-T but I checked your profile/posts and you do not seem to be technologically retarded.
If the signal sucks, get a bigger, active antenna. That seems to be the consensus on the net. Otherwise, you are SOL.
I still do not think the landlord has any obligation to provide the building a big-ass DVB-T antenna on the roof, same as with a sat antenna. I am sure, however, he made himself a deal with Unitymedia when they connected the building. If this is the case, you might even be paying for basic cable in the Nebenkosten. I'd check the Last NK-Abrechnung, and if you are, get Unitymedia to fix it.
As for the RFB/GEZ we can all bitch and moan about it forever. Until the day that referenda (Volksentschiede) are allowed in this country, there is nothing that can be done. In its current form, I am 100% against it. But, if the quality of programming would be even 50% as good as what the BBC does with its licensing fees, I'd be all in.
IMHO, it's close to impossible to find something with your requirements, near ISD (Wittlaer/Kaiserswerth), in that price range. Check for places in Lohhausen, Unterrath, Angermund, and in Duisburg (Huckingen, Rahm, Großenbaum, Serm, etc.). It's a 10-15 minute car ride, but the places there are more affordable*. There is also the U79 connecting the 2 cities, and it stops next to ISD. Settling along the line isn't a bad idea.
As for furniture, you can check the adverts in here in the NRW section. There is also a very active group on facebook (https://www.facebook.com/groups/DusseldorfFleaMarket/). It's crazy in there (in a good way).
I parked on the opposite side of the road to drop something off one cool morning in a residential 30-zone. Done this many times, and yes, I know, not legal. While I never got a stub on the window, a few days later the Verwarnungsgeld mail arrived home.
I always pay these things immediately. Later that day I made the payment, via online-banking, using the template (Überweisungsvorlage) from a previous ticket. For whatever reason, when I changed the reference number, it still sent the payment to the city under an old number. Cue a couple of weeks later: I got a Bußgeldbescheid for 3x the amount. "WTF?", I thought. I had paid that already. I checked my banking statements and there I discovered the cock-up with the reference numbers, and the fact that a few days earlier they had returned my original payment with the wrong number.
I called the city, and the nice lady on the other side tells me to appeal the fine as I had good intentions and I had tried to pay the Verwarnung.
Well, a long time has passed and I finally heard from them. I still have to pay the larger fine because the responsibility of getting them the money lies on my hands. To quote:
So I suppose I am screwed. I'll pay because it seems like a waste of time and money to appoint an attorney for such a triviality. I am still, however, bothered by the germanness of this whole affair. Ordnung muss sein, right?
By the way, does anyone have the means of finding out what the Rn 23 und 26 zu § 56 OWiG, Kommentar Göhler, 16. Auflage are? I can call up the OWiG and the specific paragraph on Google, but I don't know what the Rn are. Seems really unfair and obscure to be quoting some commentaries/footnotes/whatever-Rn-means (Randnummer?) on a specific edition of a law book that is not freely available.
Forget about hockey. Because of time zones, NHL games here usually start at midnight, if it's an East coast team. Forget the Pacific Division. Although, if you wake up early enough, you might catch the last period.