You can contact the NVC directly to insure they'e received the request to transfer your file to USCIS at your location. It may also be taking some time to process, although I understand it's been 2 weeks I know I have cases that take a bit longer just in terms of the local USCIS office getting the file back from NVC, etc.
You may want to speak with an immigration attorney if it is delayed much longer, and they can prepare you and your spouse for the interview as well as be there on the day to accompany and answer any questions.
All the best and good luck!
The answer above is a general response and should not be taken as binding legal advice. You should contact an immigration attorney to fully address every issue of your case.
It sounds like you are fine. Once it has been six weeks, if you have heard nothing, make an info pass appointment at your local USCIS and ask them to check the comptor to see if your I-485 is in their system.
Not a problem. You have done the right thing by advising the NVC about your wife's current residence in the United States. However, you should do a follow-up with the NVC to guard against any errors on their part.