You're being in Germany is a bit of bad news. Germany is the most sue-happy country in Europe. There are even specialized lawyer agencies throughout the country that do nothing else but troll local businesses using many loopholes in the local law.
What I'm saying is that it would be wise for you to sooner (better than later) register an LLC (if your project gets any traction) but not in Germany instead in some other country. Then you won't be obliged by the law to display your home address in Impressum and local lawyer trolls won't be able to get anything from you.
For the moment the best advice is to consult a local lawyer concerning legal documents or (if you write them yourself) review similar agreements specifically from German sites. You'll find there some unique shit that doesn't exist in other countries.
Addition: I totally forgot that to register an LLC in Germany you have to put 25.000 Euros on the table as the backup capital. Not everybody has that much money. In France it's about 8.000 Euros but from what I heard from some people who tried entrepreneurship in France, it requires strong nerves to deal with their bureaucracy. In Spain it's about 3.000 Euros and I haven't heard much of a complaining. Anyway, I'm not an expert and you should certainly look around and research various countries in your neighborhood (and perhaps farther away like Hong Kong or something).