This is a UK law question. See my colleague Alexander Ivakhnenko's answer above.

She needs yo apply for a Tourist Visa at the US Embassy or Consulate.

You need to hire a California lawyer to find out. There are plenty in LA.

You should, and you had better hire a US attorney and an attorney in your own country to make sure you comply with the laws in both jurisdictions.

Hire a lawyer. He will figure out if you are liable and what to do about it.

Hire a lawyer. The issue is if you have enough contacts to justify long arm jurisdiction.

That depends of the Philippines. Ask their embassy or consulate.

Yes. You probably should set up an entity in Mexico, and of course will have to comply with al employment laws there. Hire a Mexican attorney....

This is an immigration law question, Pass to that area.

This is an employment law question. Hire an employment law attorney.