Animators and Sprites

Ok i made a game, and i have to animate some spiders.
But i don't want to make a sprite sheet, i want to create each leg individually, the head, the body, and then animate them.

This is how i did it:

I created an empty object, put all the sprites of the body parts inside it, gave to the empty object an animator, and this animator now control the movement of the children...

I didn't use bones, avatar or other stuff i always read about, so my question is:

Is there a better way to do it?
How can i optimize it?
Besides i have a lot of prefabs, each one with the same animator...is there a way to optimize a lot of identic animator working at the same time?

 

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