I don't think you'll get an answer to 1/2/3 as I've seen similar things asked on Meta Stack Overflow that serves as a default meta site for the overall network. The exact rules are kept secret. At the moment the closest question I can find that's not deleted is Do the question and answer ban rules need to be secret? The person with the top-voted answer (Shog9 when not in a Christmas mood) is a Stack Exchange employee.
You could start by taking Olin's advice. I can't view your deleted questions / answers (which count towards the ban as well) but all your content that's been down voted contains numerous spelling and grammar errors, missing spaces, abbreviations and sentences that start in lowercase. Maybe you could copy it into a word processor and use the spelling and grammar feature to help pick up anything you've missed.
As for my personal opinions:
Flagging obsolete comments - I'd probably forget that one, in a previous question someone had declined your flag and W5VO said it was a low priority for inactive questions. You'll probably just annoy everyone if you raise a huge number of flags and if too many get declined it'll likely have the opposite effect.
I'd consider editing a positive contribution and wouldn't be surprised if they're taken into account in some way. But be careful they're not trivial edits just for the sake of it and they fix everything without introducing new errors otherwise they'll get declined.
Who knows if voting counts but it's always nice to up vote if you see good content. Just don't go through and blindly do it on everything on the front page or a particular person, that sort of serial voting gets detected and reversed anyway.
As it's a question ban you could also provide some answers to any questions you find unanswered (or where you feel you can provide a better answer) but make sure they're correct, good quality and don't include any of the problems I've mentioned in the second paragraph.