I need help with making very unusual melee fight system

I want to make game about hunger games and i want to make very unusual fight system:
In every game when you left click you hit someone exacly where your crosshair is.
I want to make a system that when you are holding left you need to slide mouse like a real weapon (faster=higher damage) (if you hit neck (fast) you can cut off head, leg etc.)
And the same with deffence-when you hold right you can move your mouse (weapon) where you want to dodge.
I need to know:
-How to make this system
-How to make animations for moving weapon (like slicing from the right and left side)
-How to make hitboxes (like when you hit neck you cut off somobody’s head etc.)
-How to make something like cutting of head, hand etc.
-How to make speed categories (if you slice neck example: in 500 centimeters/second you cut off his head, but when you hit in 300 centimeters/second you only slit the throat but still kill)
That’s first person game

If anyone know how to do that please tell me down bellow i know that im asking for a lot but i dont know how to do that i searched everywhere but i cant find anything of this. Please help me.