1. No other documents, GC copy and divorce decree are sufficient.
2. Only what was sent to them, and perhaps taxes, but not necessary.
3. I really don't want to bum you out, but my experience was horrible. My officer was asking questions about my marriage and reasons for divorce, but did not ask for evidence (they can't based on 5 year residency). At the end, she gave me the "Decision can not be made yet" result and held my case without a decision for 9 months after the interview. Worst 9 months of my life. 2 senators contacted USCIS in regards to my case without any result, but they finally approved after I contacted Ombudsman.
This process is very stressful so try not to let it get to you. They can try to make it hard on you, but everything will be okay in the end. Good luck