Multiple Models sharing the same Animations?

This is probably a total noob question, but I'm completely new to Unity, so I figured I'd ask before I go and try my own thing for several hours to find that it doesn't work.

First off, animation sharing.

I want to make a generic set of pistol animations, firing, reload, running, meleeing, etc. and rig not several different pistol models, but several different pistol PART models to share this animation, so that players can combine different slides, frames, barrels, and accessories to make their own customized weapons. Another example would be another game I'm working on where I want players to be able to combine different blades, grips, pommels, and cross guards to create a custom sword, but I want all the different parts to follow the same swinging/stabbing/finishing move animations as one solid weapon.

Second, animated skeleton sharing.

Let's use the simple example of making one human skeleton, with all of the necessary animations, and assigning it a male and female body model to share the animations and skeleton. I know I can cheap out and just copy it, but I'd rather not do that, as I intend to have a LOT of animations all shared between ten or so meshes, and I can see this taking up enormous amounts of memory in no time at all. On top of that, I'd want to add clothing and equipment that could share the same skeleton and animations, but would replace the mesh of the body underneath it to prevent unsightly clipping, and also just because I think it'd be incredibly inefficient to render one mesh that will, at all times that it is equipped, be completely blocking out the model underneath it. For example, if a player equips a glove, the character's hand stops rendering because there's a glove over it. But I'd also like to be able to tell the game to leave the underlying mesh rendered for certain things, in case they don't cover the body part entirely.

How do I do all this?

I'm no stranger to programming, so I don't need someone to hold my hand and tell me everything I need to do step by step, I just need to be pointed in the right direction, or be told that I can't do this in Unity so I don't go and waste my time trying to figure it out.

Actually, I remember from modding TES4 that they do the same thing for characters. Hopefully if my request is confusing that might help clarify. I think Skyrim probably does the same thing, but I've never tried modding it so I can't say for sure.

I'm also using Blender for all my models and skeletons and animations, and the FREE version of Unity.

Thanks in advance

Edit: This doesn't even need to be done straight from Unity, could this be accomplished with some clever scripting or something?