That's OK. Even if still married, you can apply under 5 year rule.
Sure thing. You will be asked to confirm dates of your travel and sometimes addresses and work. You don't want to give officer any reason to question you more.
I had about 7 trips since I became an LPR and I remembered all. My case was squeaky clean, so the only thing officer attempted is asking me to confirm wrong dates which I corrected. Theoretically, officer can accuse you of lying under oath if you get any info wrong. Or start playing games: "You said you returned to the US from Australia on April 9, but your application says April 7th."
Here is my story:
My understanding is, the officer tried failing me on a technicality. Even though case was straightforward, she could have made it hell if I didn't pay attention. She even had an apprentice sitting there, potentially there to learn tricks and how to probe people.
After approving me, she even took same elevator with me and lawyer down to the lobby. Even though I was relieved, I kept my comments etc to myself and had mouth shut when going downstairs in the elevator.