Holy crap you have a ton of links at the end. But I love your reference to Back to the Future, Hitler, and the Butterfly Effect. In regards to your hitler example, just because he wasn't killed doesn't mean time travel can't happen. If people could travel through time, maybe they have different motives than killing hitler. Just my two satoshis.
Interesting. I wonder how many times Marty died in BTTF. I'm writing a new article about that right now which will feature a video on that theory I just found. Yeah, I get that time travel may be possible even if Hitler is still around. I know there are a lot more variables than that. I borrowed the Hitler argument from somewhere. Don't remember who said it but I decided to pass it along. Interesting argument concerning Hitler, but still just an argument.