Aah, the bloody thing is over!
So, our interview was done on 3/28. We arrived half an hour early, San Jose field office looked empty, we were admitted almost immediately. The officer was neither friendly nor anything, I couldn't read off his poker face a thing. My wife, the winner, took the turn first, took the oath and then went through every single question on I-485. Then had to sign that she agrees with all the notes/corrections the IO made on her I-485. Was asked for her original birth certificate, all letters from KCC and the DV fee receipt. We had our kids with us, so were asked for both their birth certificates, even though they're US citizens.
Then I took the oath, and went through all the questions on I-485. My bad here, I had an out-of-state drivers license - I'm in consulting, move a lot, and my employers' headquarters are not in California either - so IO started asking about something that would prove that I live AND work in California, like apartment lease (didn't have it with me) and tax return (had it but FORGOT about it), or employment letter - asked if I had HR in Cali to get it the same day. I did show him my payslip, but that didn't satisfy him. I must admit, I was a bit shaken, in part due to lack of sleep the night before, in part due to not being ready for some of the questions. So I could give him W-2 that I had with me but I didn't, and I even forgot that I had all my tax returns at hand. He also asked for original marriage certificate, divorce certificate from the previous marriage. Then he turned back to my wife and said that since she's is unemployed she'll need I-134 affidavit of support. We said that we have proof of sufficient funds, but he responded that she must have an affidavit if she's unemployed, and he's going to verify if I could sign it. I spent the next couple of minutes trying to think who would do this for us if he tells that I'm not able to sign myself. Fortunately he said that I can do it, all I needed was to provide my I-94 number against option (e.) in question 1. on the form. At this point we had so many unanswered questions accumulated that I was starting to wonder which way it might go.
So he gave us a request for additional information, asking to provide within 30 days: employment letter, apartment lease, tax return, affidavit of support by me on behalf of my wife. Then he said that KCC file had not arrived yet, so he'd be working on that while we prepare all the documents. My wife was never asked for original high school diploma, which is ironic since most of other folks seem to get away with showing just that.
I got employment letter from HR on 3/30 and immediately overnighted all the docs. We've been nervously waiting since the date they were delivered, and Hallelujah, Card/ Document Production emails are sitting in my inbox for almost an hour now!