Stuff2447

Her green card will automatically be extended for up to 24 months via the Receipt Notice for the N-400. There is no need to file an I-90 when filing for citizenship. https://www.uscis.gov/newsroom/alerts/uscis-updates-policy-to-automatically-extend-green-cards-for-naturalization-applicants

It will be easier and fast to just re-apply. You had three chances to take the oath and you declined three times.

Filing the I-751 is not optional for your wife, if she plans on keeping her green card. She is expected to be in the United State for biometrics and to attend an interview, if required. You cannot request an interview in your county to remove conditions on her permanent residency. A green card is for permanent residency in the United States, and is not to be used as a tourist visa to come here once in a while. The fact that she has been away the entire time of her conditional residency virtually guarantees that the interview will not be waived. Be prepared to explain why you were away the entire time since she was granted conditional permanent residency. If you do not intend to return, she can file an I-407 to give up her residency and start over once you intent to actually live in the United States. The better plan would have been to not even sponsor her until you were both ready to actually live here.

The wrench in your plan is that it is currently taking a very long time (years in some cases) to approve the I-751 (removal of conditions). While the N-400 can be filed on the schedule you presented, the N-400 cannot be approved unless and until the 751 is also approved. So, in other words, the pending 751 may cause a delay in approval for the N-400. Sometimes they are adjudicated together, sometimes they are not. Hopefully, in a few years, this situation will improve.

She posted how it went above. Scroll up to see her "update" from 2013.

They will re-schedule your interview. You absolutely cannot just show up and expect to get interviewed at your convenience! Ignore those on here telling you that. You can't even get in most USCIS buildings without an Interview Letter/Appointment.