Best advice you'll ever get is to: Stop.
The more you think, the more Satan sees a chance to deceive you. If you do have any legitimate doubts, then contact a Mufti so that he clears them out for you. Don't be the one to lose faith because of overthinking.
I'm not sure about questions 1, 2, and 3, but I saw on IslamQA (Hanafi) that if somebody exits the fold of Islam while they have wudu, then reenter, wudu will not break unless he has done something to break wudu. Here is the link: https://islamqa.org/hanafi/askimam/14755
Your distress about these thoughts indicates a clear sign of faith: ...