Firstly, don't get offended when I make a comment. If you want to avoid people making certain comments, be more descriptive. You make it seem like she's never lied to you or her parents. People don't always tell everyone everything.
Secondly, do you really think her dad is going to kill you so that he can go to jail and not be able to protect his daughter from others? He went to jail, but did you ever stop to think about how long ago that might have been or what it was for? I can assure you it most likely wasn't a serious felony, because if it was he most likely would have been disbarred. Her father was using a scare tactic in order to get you to remember who the boss is and who you have to answer to if you break her heart. If you're the good guy and all her other ex's were assholes, why would he want to kill you when he could have killed them?
I know that it sucks. You want to be with her, but her parents are an obstacle right now. If she is really ready to stand up to her parents regarding your love for each other, she shouldn't let them come between you. She shouldn't make you wait two years until she moves out. But if she is dependent on them for now, don't be surprised if she does. I'll be honest, if my mother didn't like my gf and told me that I'd have to move out and that she wouldn't help me unless I broke up with her, I'd move out. There would be no one standing in my way of being with my gf.