Skirts are always a problem. Aiko comes in with her legs slightly bent. (Which is annoying to most of us, but necessary for animators.) First, turn IK off. (Under Figure -> Use Inverse Kinematics.) Then, zero her. Select Aiko's body, then Window -> Joint Editor -> Zero figure.

You are still likely to have trouble with her legs sticking out of the skirt when you pose her. (It's an inherent problem with Poser.) Most conforming dresses, including the Ruffle Dress, solve this by including "pose morphs" in the skirt. These let you shape the skirt so it fits. They are called things like "LegSideL," "LegSideR," etc., so you can generally figure out what they do. Sometimes these are in the Body of the dress, sometimes in the Skirt, sometimes in the Hip.

Not sure about the hair problem you are having. What hair are you using? Are you sure you're applying a hair MAT file, and not a pose file?