Nice to hear from you again.
1) There is indeed a risk to get deported if your asylum procedure ends with a negative result since authorities already have your passport. They need it in order to send you back to your home country. But this won't happen before you receive a decision by BAMF. Even it turns out to be a rejection you can still file an appeal which gives you a little more time to marry.
Also, after all your documents have been checked by Standesamt and a wedding date has been set (in other words: when your wedding is imminent), it's not lawful for Ausländerbehörde to deport you anymore (in accordance with AufenthG §60a (2): https://dejure.org/gesetze/AufenthG/60a.html).
2) It is possible for German authorities to refuse to give you a residence permit if you for example commited a severe crime or if you are a danger for the security of German society or the German state (--> https://www.gesetze-im-internet.de/aufenthg_2004/__25.html). But a fine for fare evasion shouldn't be a problem.