I had my N-400 interview today in the Fairfax, VA ("Washington D.C.") office, and took my wife with me. Upon entry you first go through a security checkpoint where they do not ask why you are there, so my wife and I just walked in. After that someone saw my binder with all information we have previously submitted, and asked "Interview?", and pointed us towards the elevator to the second floor. At the registration counter I showed my N-400 interview invitation and told the attendant that my I-751 is also still pending, so I brought my wife, and she replied "It's possible he will make it a combination interview then.". After only a few minutes the officer came to get me and my wife, and I explained that I brought my wife in case he would like to also go over the I-751 stuff, and he says "that would make sense, especially since she is here already and then we can take care of all that in one go". We first did the N-400 interview itself, going over the form, adjusting small things (our address was updated based on automated USPS system feedback), going through all the yes/no questions, and he asked me 6 questions which I all answered correctly (he asked me "Who is the father of our nation", "name one of the branches of government", "what happened at the constitutional convention", "what date are taxes due", and two others I forget..). I had to read a sentence (Who is Abraham Lincoln), and write "Lincoln was the president during the civil war". We then went on to the I-751 part, he asked some basic questions to my wife such as "how did you meet, how did you start dating, did he propose to you, why did you get married?", and then he asked me "when did you get married, why were you the one proposing". He asked if I wanted to add any other evidence, and I told him I had some additional pictures (13 printed on two letter pages), and he would add those to our file. He said we were approved for both I-751 and N-400, and that I'd receive a notice for the Oath of Allegiance ceremony very soon! I can't wait, finally done with all this bureaucratic red tape!
You don't have to send your spouses birth certificate at this stage, but you will at the NVC stage, along with an English translation. I sent a copy of my spouses passport with the I-130, but it's not required. You should try to send your packet as complete as possible, but most likely if something is missing you'll get an RFE. Good luck
It's critical to read instructions carefully and interpret them literally, including words like "or". Send a copy of your Naturalization Certificate, in color, even though the certificate says not to copy it. That's evidence of US Citizenship. The only reason you would also send ANY of your passport pages would be as evidence of time spent together in person in the beneficiary's country, or in the case of time spent together in a third country, the applicable pages from both passports. Only if you lost your Naturalization Certificate, would a Naturalized Citizen send every page of their US passport as evidence of US Citizenship. Keyword is "OR".
