MMORPG character creation, working with armor and different faces

Hi,

I am new to Unity 3D and C# code, although I believe I can master C# relatively quickly, I am working on a 3D MMORPG (similar to Skyrim with the first person view) where every new user can make their own character and customize it (face, eyes, hair, class, etc.).

I am wondering how I will "program" this into Unity, should I use some other 3rd party Unity mod to do this? Or can I create a mesh and do all the avatar stuff in the Unity tutorials for my characters while the game is running?

Second, how would armor work in terms of modifying hitboxes when equipped (like a thick armor would make your hitbox bigger) and armor that moves WITH the arms and legs as they move, how would armor stretch as you swing a staff or open a door? How do I make these things work?

Thank you in advance,

leapformula4