1. Comparing bisexual to pansexual is like comparing trees to plastic.
2. The whole pansexual thing is no leans in gender whatsoever. They do not prefer genders.
However, they could date more demigirls than any other gender. But it's not a preference, just a coincidence.
3. Bisexual is TWO genders. Doesn't matter which two. And it isn't blindly, so they can have leans. My girlfriend had a male lean.