How would I to allow part to move freely while playing animation?

The roblox animation editor makes animating anything way easier, hopefully thats the same with everyone, but what im wondering, is how would i make the animation more "dynamic" in terms of the part being animated is also dynamic, moving around with a script to certain circumstances. How would i go about doing this, without ruining the script. In my case i would be using the roblox animation i make while also having the players torso/arm move with the camera to make a more third person experience, i could go about making the animation via cframe, but would rather have an easier time and use roblox's animation editor to play the animations. I would like to use a weld, but if there is a unknown property of the motar6d for the arm that i dont know about, that would allow such use, then i would be fine with it, as long as its cframe compatible, and preferably base via the Part0 local space, but i can easily convert local to world space with roblox's function if not so. To put things short, i need:

1. To have an animated part be able to move freely
2. Have that part be animated with roblox's animation editor, while still being able to do said thing as said in 1.

The short answer is, you simply can't. The long answer is, When a part is animated (in this instance a body part) it's put under a whole new law of physics, think of a movie. The body parts move by a premade animation set up, it's all linear. Changing the CFrame on animated parts won't really do anything other than probably create random bugs and unwanted effects. On the other hand, when a part is moved by a CFrame force, think of a first person shooter, it's movement is based entirely on for example mouse movement (gun aiming is a good example). What you're trying to do is like making a muppet that has a up-down moving jaw and expecting it to bend sideways. However, you can mix animations with CFrame (like I did) to create some nice looking effects, like animating the torso to rotate in a specific way so your character is sideways but moves forward and the arms animated in CFrame so they move relative to the mouse, creating the illusion of aiming.