In trying to understand Orthodox Judaism better, I would like to know what constitutes the "minimum" or most basic collection of beliefs. As I understand, agreeing with the 13 Principles of Maimonides is a great start, but I am a little confused on the exact nature of belief about the Talmud. As well, how much of a margin is there for personal opinion? Thus, I would like to know:
What is the most basic collection of beliefs absolutely required for one to be considered Orthodox (esp. MO, and ignoring other, non-belief related requirements, such as one's actual practicing of mitzvot)?