Ree

I know somebody who applied for a replacement card last summer, and received a new card last month. So, it was about 8-9 months of waiting.

10.
4.

I am so sorry for you loss...
As for ROC, you can go ahead and apply now, just check in I-751 that you are applying as a widow, and include a copy the death certificate.

You cannot skip biometrics on your own. Sometimes they can process N400 using previous biometrics, but if they want to to go and take biometrics, you MUST go. Otherwise, your N400 will be considered abandoned.

There is no need for a cover letter.

Did they close your case because of your failure to appear? If they did, you need to start the whole N-400 process all over again.

It depends on where you live and how busy your local office is. Can be anything from a couple of days to a few months.

As far as I know, SS office won't give you a SSN card with your new name unless you have updated greencard matching your new name.

I am just wondering If you are thinking to send her N-400 while she is out of the country, what are you planning to write in N-400 about her trips? I mean that question in the application about the trips she had taken, as well as the numbers of the days she had been out of the county. How do you guy plan to count her current trip if she is still on that trip?