Can I enter the US with my turist visa while K-1 is in process? Could I enter the country more than once?

This is an immigration question. Pass to that area.

How can i get proof of immigration from Cuba? I was an infant i entered 3/1970..i want to apply for a HE 11 Visa to vista Cuba

This is an immigration question. Pass to that area.

In general, yes. You need to hire an international business lawyer and explain the nature of the transaction and with whom you wish to deal.

How can I bring my friend from lebanon to the us for a visit?

This is an immigration question. Pass to that area.

Can I do business with foreign clients with an LLC?

You probably would be able to do it for a while if your billing and banking was from the US. However, generally if you stay in a country more than...

This is really an employment law question. Pass to that area.

Can I file I-485 for an approved I-130 while my parent is in US with a tourist VISA?

This is an immigration question. Pass to that area

This is an immigration question. Pass to that area.

Tax implications of investing in a US startup, but investor is Canadian?

This is an extremely complex question way beyond the scope of this forum. Hire a lawyer and make sure all the necessary steps -tax and otherwise-...

Can you name some international non profits in the US that provide G4 work visa (apart from UN and World Bank)?

This belongs in employment or immigration. Pass to Employment.