Most efficient way to display items on a character?

I'm unsure how to display the items a character is wearing.

I understand that, to make a character 'hold' a weapon or item you simply attach empty nodes in the characters hands but, how would one go about changing the clothes texture.

I could just change the material texture to change its look but that would limit the customisation to just a few outfits instead of enabling the player to mix and match, for example, to wear blue pants and a green shirt instead of an all-green outfit.

Do I create separate meshes for legs, upper body, hands, ect. and attach them to the same game object so that each mesh can have its own material? If so, does that mean that each part of the body has to have its own armature and animations? That seems awefully heavy and inefficient, but I have no idea how one would do it any other way.

Another related question I have is...is it more efficient to have one mesh per game object or everything connected to the same mesh? I would like to have a game object with a hidden mesh and animations that would be activated at a certain time.

By efficient I mean less costly to run.