No he would need to remain overseas while the K1 is pending. He may adjust status in the US but that cannot be the intent upon entry. Consult with...

This does not appear to be a criminal matter so can be answered as you indicated.

Can immigration at the airport tell you that you have to leave the US in 45 days instead of 90 days?

Yes they may do so and have the authority to limit your visit.

Can a green card holder get pregnant?

Yes there is no bar against a LPR getting pregnant.

Can the 1 485 be denied when the 1 130 still pending and not totally revoked?

More information is needed about your case so it is best to consult with an attorney for guidance.

What should she do? Can she lose her LPR status?

Yes a person may lose their permanent residency depending on many factors including crimes committed.

Could you tell me, please, how is my chance to successfully apply to N400 and not be deported?

You should not be deported and you are eligible for naturalization based on the information you have provided. Consider consult with an attorney...

If the I485 is employment based then quitting your job is not advisable at this time. Consult with an attorney prior to changing jobs.

Appearing on MASTER hearing without lawyer

She should attend the master hearing and inform the IJ at the time that she does not have an attorney and would like more time to work with one.

I lost green card just before citizenship interview

The receipt of duplicate green card as well as previous copies of it should suffice for the interview.