1. Ask a lawyer has US attorneys who are very unlikely to know anything about Dutch law.
2. That would be the subject matter of a contract between you and the company. Without proper visa status, however, you could not act as an employee in the US. I think you are saying you will work in Netherlands for the California company. There is not such thing as an "official" employee versus and an employee. There is a difference between an employee and an "independent contractor".
3. Much will depend on what type of entity, whether you will "earn" it or "purchase" it. Employee Stock Option Plans are different than the purchase of equity in a business.
4. What else needs to be done? That is so fact intensive that it cannot be addressed here.
Bien cordialement,
Answered on Dec 22nd, 2014 at 12:34 PM