You can continue to stay in the country once your file a MTR or for the time allotted in the decision if you do not file MTR. Your EAD is linked...

The burden of proof lies with you. You should be prepared to show that you have a bonafide relationship.

If you are renewing your 10 yr green card, the fees is $465 for paper filing and $415 for online filing.

You can seek help from your local congressmen to see if they can help you. Meanwhile, keep contacting USCIS. If you paid your filing fees by credit...

You can file with the most recent one however, I'd also recommend contacting CBP to correct this issue as well.

Depends if you want to file it inside or outside United States. I recommend talking to an attorney to see what process fits your needs.

Pay them separately. If they reject your filing for some reason, they will destroy the G-1450, you'll need to resend it.

It may be hard since the EIN number will be the same. You may want to try contacting USCIS for technical support.

I recommend that you inform USCIS that you will be withdrawing your extension and indicate you will be leaving by sending in your return tickets....

You can always get all the paperwork ready. Once you have the naturalization certificate in hand, you can file right away.