US Immigration from Nepal

What is visa bulletin current date? Is it the date when NVC case was created? Or is it the interview date?

I submitted all the required documents on FEB 18th 2020. But I haven't got any emails or anything confirming their receipt.

Considering all the documents meet the standard, how long should we wait to get case complete notice? and how long should we wait for an interview? Our interview will be in Kathmandu, Nepal.

Please share your experience on wait times.

I currently have a non-immigrant visa (B1-B2). I am intending to travel to
the United States in June 2020 with my B1-B2 visa.
But in the meantime, I might be getting an immigrant visa before June.
Will having an immigrant visa revoke my non-immigrant visa?
I am not traveling to the United States with an intention to immigrate in
June. Furthermore, in order to immigrate to the United States, I would have
to travel with my mother because she is the principal applicant to the
immigrant visa of which I am a derivative beneficiary. And my mother is not
travelling with me in June.

Guys,

My GC (from marriage) is since 5/9/2017 which means I can file for Citizenship 2/9/2020 right?

Thanks

I got notification about DQ last week. Don't have any idea that how long it will take to get interview date after DQ in nepal. Another question is do I need to send original form of I-864 affidavit of support to my wife for interview or scan copy will be good? Please help me.