How can I remain in the US and continue to work for my host family after my J1 status has expired?

Hard to say without consulting with an immigration attorney.

What is the best legal route for me, a green card holder, to have my fiancee join me in the USA?

Best to discuss the with an attorney in private.

Attorneys cannot solicit you. You’ll need to contact attorneys to arrange for consultations.

How much would a lawyer charge to write a business contract for catering staffing services?

Depends on the firm. You’ll need to speak with different firms to see if your matter is something they’ll do for a flat fee.

Travel aboard when your N-400 decision cannot be made.

Hire an attorney to review your case. It’s unclear what level of risk you present to yourself if you travel.

Can a US national legally own or manage an offshore incorporated company providing that...

Hire an attorney to review and offer a reasoned opinion.

Can I be arrested or charged with any crimes or misdemeanors for posting a video online that isn’t mine?

Hire an attorney as soon as possible.

Speak with an attorney about this. They will need to review your agreement and speak with you at a minimum.

Need help on divorce and immigration help on i485?

Please consult with an attorney about your matter. It’s very difficult to give specific advice in this forum.

If I start an LLC during my marriage do I share operational decision making with my wife or just ownership?

You don’t provide enough information here. Best thing to do is speak privately with business counsel.