If I wanted to purchase Ineisis Online (Source Code) do I need to have access to the EE source code to make this work, or would a basic license monthly suffice?

No, you do not need Esenthel source code to work with the ineisis online source code.
Ineisis is just the source code for the game mechanics in that game not related to the game engine's internal code.

Meaning a monthly license would suffice.

Ok awesome.. I do want to get the source code license but my budget doesnt permit atm, so Im stuck with the monthly for now... Im hoping at least the Ineisis source can help bring in a small income in months to come.. Since, it gives the source for paypal payments, and setting up and account, and multiplayer...