Eligibility for relief depends on your conviction. If you were convicted of a child abuse crime, you may be ineligible for relief and can be removed from the U.S. except for protection under the Convention Against Torture. My best advice would be to immediately consult with an immigration lawyer to determine if you have defenses to removability.
Yes , you may marry in one of the states that recognizes same sex marriage. Currently, there are 12 states and the District of Columbia where same sex marriages are recognized. Once you are married, you should consult with an attorney to assist with the residency petitioning process.
Generally, you do not get approved on the spot. Once the interview is completed, the officer may review the case and at times, may also review it with his/her supervisor. If any information is missing, you will be notified and be provided with time to submit it. If all documentation is complete and there are no issues, you will be notified in timely fashion.
You will need a temporary visa that allows you to work. A green card in the short term is not a viable option. You should consult with an experienced immigration attorney to advise you on the best course of action.
Your friend's husband needs to contact an immigration attorney immediately. The attorney will determine whether he's deportable and whether he has any basis for relief. If he arrived in the United States as a child, graduated from high school or obtained a GED, he may be eligible for benefits under DACA.
Since you came in on a crewman visa, you are barred from changing your status in the U.S. In order to change your status you will need to consularly process. Other issues may be raised during consular processing, including unlawful presence. The best advice is to consult an experienced immigration attorney.