Move to another state after applying for us citizenship

Once you move you should file a change of address. It may delay your case but likely not considerably.

No you can attach one set of supporting documents for the entire application.

Can I file Fiance visa without making above poverty level on my last tax return?

You can file a fiancé visa and use a cosponsor for the financial support requirements. It would be advisable to consult with an experienced...

My n 400 application interview was descheduled, what next step should I take? Why does uscis deschedule interviews?

It is uncertain the basis behind your rescheduling but this does happen when there is a scheduling conflict.

It may be another few months before you receive your EAD after the biometrics have been completed.

Adjustment of status ?

If he is required to file taxes then there is no way around filing and reporting the income on the affidavit of support for immigration purposes.

#Immigration: Is that required to include driver's license and G-325a in the adjustment of status application?

No you do not need to submit a driver's license with your form G325A.

Is that possible?

Yes as a USC you can petition for your siblings for an immigrant petition. Keep in mind however that these cases take anywhere from 12-14 years...

Got i-485 RFE and i-485 approval welcome notice letter simultaneously.

You should likely wait a bit until you act, and if you do not receive your green card, schedule an Infopass appointment to inquire further.

When will USCIS reschedule my AOS interview?

I agree with my colleagues - it will likely take a few months before another AOS interview is scheduled.