Welcome to our community and thank you for your question!
@Miky already gave you a great overview - thanks for that!
Let me just add a few things that popped up in my mind:
3) In general, I would recommend to avoid Eastern Germany and Bavaria because these federal states tend to be more conservative and/or to have a stricter interpretation of the legal-framework. Also, living in a bigger city is probably easier because people are usually used to a mix of international people (compared to small villages in the countryside). That will make it easier to integrate.
5) Yes you can, but keep in mind that it's going to be complicated to marry if you've already been rejected. Authorities will most likely try to deport you if your asylum procedure is over. If you want to know more about this topic, you will find extensive information here on Wefugees.