If your U visa is not expired, you could file to renew the EAD. If not, you will have to file for an EAD based on your pending adjustment of status.

It seems to me the answer is yes. It is not asking if the spouse is a derivative, just whether to process the applications together.

If you did not work without permission, and if USCIS never made a finding you were out of status, then under the current rules you should not have...

As long as the receipt is not expired, then yes, you can travel with an unexpired passport, expired green card, I-90 receipt.

USCIS is taking up to two years to process EAD's, but you are right they are usually faster if the EAD is based on a just approved VAWA application.

It seems to me that you would be subject to the Adam Walsh Child Protection Act and you would need a waiver to get a petition approved.

Sure, there is no rule against you filing a new application for a U visa with a waiver, to get your status back again.

There is nothing she can do. She is obligated to support him based on the affidavit of support she signed, so she should make sure he naturalizes...

USCIS can be very slow in getting receipts for such motions, check if CIS cashed your check, follow up with the lockbox if you filed by mail.

It seems to me that the CBP officer might question whether you could be an intending immigrant if you filed for a green card.