Hi The Thus,
Welcome to Moz Q&A!
Wow, you have several questions. Frankly, none of them are directly related to this discussion thread about the new Domain Authority. In light of that, you may want to consider starting a new thread that is focused on your most pressing SEO question. The more specific the question, the more likely you are to receive helpful responses.
You can post a new SEO question here:
https://moz.com/community/q/ask
You can also get tips for getting the most value from our SEO forum by following that same link.
I hope that helps!
Christy