There are too many issues in your question to address in this forum.
Basically, if your overseas "partner" isn't going to be an owner of the business, you should have a contract with them that says what you're going to pay & what they have to do to earn the money. The terms of the agreement should be specific, and unless it's a commissions, should probably not be based on revenue. The LLC operating agreement is only between owners of the business, so everyone needs to be clear on whether she's an owner, an employee, or merely a contractor.
The fact that she is overseas has a huge effect on the logistics of the business, the type of entity to be formed (if she's going to be an owner) and the difficulties in enforcing an agreement with her.
There are many options to consider, each with its own pros and cons, and you'll need to sit down with a lawyer in your area to determine the right answer in your situation.
I agree with the previous answer. There are way too many issues in your question to address in this forum.
First of all, you are confusing "partners" with "members" of an LLC. Although they might elect to be taxed similarly, a partnership structure is different from an LLC. An LLC's Operating Agreement only covers members and managing members, not employees. Members of an LLC are the owners (similar to shareholders of a corporation). In California, an LLC can be a single member LLC.
Secondly, you do not mention what type of business you are starting, and why the overseas person can remain overseas and yet provide labor and expertise for the business. How big is the business, and will there be other employees, contractors, officers, owners? In California, certain types of business cannot be formed as an LLC.
Thirdly, your question asks about tax advantages/disadvantages but does not mention whether the overseas person is a U.S. citizen/permanent resident authorized to be employed by a U.S. employer.
Before you can intelligently structure your new business, and your legal relationship with the overseas person, you will need to consult with both a business lawyer in California as well as a tax accountant familiar with international tax laws.
Because your overseas colleague will not be a member (owner) of the LLC, the LLC's relationship with her will not be specified in the Operating Agreement - it will be specified in a separate agreement between the LLC and your colleague.
I have worked with many overseas clients and counterparties to transactions. The fact that your colleague is overseas will have modest effect on the LLC's relationship and agreement with her.
Your last two questions are somewhat vague or unclear, so I do not know how to answer them.
You should retain a business lawyer who will analyze your requirements and help you put together the appropriate relationship and agreements.
Disclaimer: This post does not constitute legal advice and does not establish an attorney-client relationship.