A signed letter from yourself and your employer should suffice.

When filling in Form N-600 , Part 2, Question 16 C , do we check off "Permanent Resident" or do we check "Other"

Their status changed to US citizen along with yours so that is what you should indicate on the form..

Can a green card holder apply for a reentry permit from abroad?

No, you must submit it while you are in the US.

H-1B visa expired on 30th Sep'2015. Extension was filed and received RFE. Is it possible to make a switch now?

Yes, if it was filed on time then the new employer can file for you.

Is USCIS correct?

Yes, real estate property must be in the United States.

CSPA, please HELP! - (Aunt in USA and We are in BANGLADESH)

You have to subtract the time in between the receipt date and the approval notice date from your age, and only if that age puts you under 21, will...

How Can I Obtain A PassPort For My 6yr Old Child ?

Both parents have to sign in order for the passport to be issued.

How I know how much I consumed of my H1B six years limit ?

You add the dates and that will give you the total amount of time.

Which one will be the change of Status Effective Date (H1B to F1): Date of Approval Receipt Notice or Date on I-20?

The effective date will be stated in the Approval notice that you receive from USCIS.

When am I due to apply for citizenship?

The date has to be counted from the date the permanent residency card was issued to you and then add 2 years and 9 months from that date is the...