My priority date became current in January 2015. I received email from NVC in June asking for my approval notice.

Best course is to consult an attorney.

H1B

Need more details to understand the situation.

Visa... Immigration

What did you hope to get from this act? Maybe there are existing ways to do the same thing.

Sorry, but what is a sovereign citizen?

Removal of conditions for conditional resident but became an American citizen

If you are a citizen, then you should be free of any issues about removal of conditions. Also, your spouse is off the hook regarding I-864...

I-751: Does one-year extension included in NOA receipt notice apply to me if my CPR was terminated prior to filing?

Suggest you consult an attorney and bring all relevant documents.

Do you have to meet the income requirements at the time you file i-864?

General principle: anything you file with USCIS must be approvable at time of filng.

Is there anything She can do?

Best option is for her to make an InfoPass appointment. She can do so online at the USCIS web site.

H1b/ h4/f1 question

If she gets F-1 then unlike H-4, her status is independent of yours. That is, even if you lose H-1B status, it doesn't affect her.

I want to apply for my sister Form I-130 (alien relative). May I apply for her unmarried children over 21 y/o in the same form?

Your brother in law can derive status from your sister but not your 21 or over nieces or nephews.