Character Customization tutorial, Blender considerations

I've been mucking about with Blender and Unity 3d for the last couple of weeks just trying to figure out the general flow of things. I recently downloaded the Character Customization tutorial from the Unity site.

In the tutorial they have male and female models that are split into the various parts of the characters that are customizable. I was curious so I found an .fbx viewer application and looked at the male and female files and it looked like all the parts were in the same file but the individual parts also existed as independant files. What I'm wondering then is the best practice, from a Unity 3D standpoint, to create character models in blender.

• Is it best to break the character into parts? arms, legs, head, torso, eyes etc?
• When you break them into parts in a single blender file does unity recognize them as seperate parts or do you have to break them into seperate layers or files within Blender first>
• When animating how does having seperate parts work when doing the bone assignments?

Sorry for a few questions there. But I'm quite curious how that works. It looks like, in the tutorial, that the script goes through and creates the database of the various parts based on the folder structure in Unity and the filename formats and I'm just wondering about the blender to unity aspect that would get the meshes, textures etc to that point?

Regards!