Yes there are many pro bono organizations or attorneys who offer reduced fees.

Do I qualify for unemployment insurance?

It appears you may so may apply without consequence to your immigration status.

This would not carry much weight unless the attorney was a witness to your birth.

You may only apply for the advanced parole with pending I485.

Question about I-601 Vaccine Waiver K-1 Visa?

You will need the I-690 waiver for such situation.

How many days i can travel with gc ead with travel document after interview while waiting for green card?

There is no requirement but best to keep departures less than 6 months.

Do you think it is a good or bad decision?

Very difficult to determine so best to wait for decision to be mailed.

Yes you may file a fee waiver if eligible.

What is the best way for my family to come to the United States as permanent residents?

Best to consult with an attorney to discuss your case of consular processing further.

(1) Is there in anyway divorce could prevent me of getting citizenship

No divorce should not prevent one from obtaining citizenship.