Is the i-821 based on TPS or DACA? Check the USCIS website for processing times.

If you entered the U.S. legally, then you file an I-130 and i-485. If not, then just and I-130.

No. They need to take your biometrics.

Renting the apartment should not be a problem. But your low income may be a problem.

It takes about seven to eight years to get a decision on a U visa application.

No, owing someone money does not prevent one from getting a green card.

It seems to me that your spouse can file for adjustment of status based on your I-140, and that you can request cross chargeability to get a...

Yes, he can send anything he wants. However he does not get to determine whether USCIS will grant or deny your application and USCIS is precluded...

Your fiance can bring it to the K1 interview.

It should not preclude one from getting a student visa in the future.