First of all, is a variable for a sprite unaffected by it's clones? Do the clones each receive their own value of the variable?
Does the “x position” motion value grab the x position of a specific clone accessing the value, or rather the sprite it originated from?
If not, what is an alternative way to manage a clone's specific data?

Sprite Specific Variables should be labeled Clone Specific Variables. Each clone gets its own copy. All system variables are also clone specific, such as costume, x position, y position. There is no way for another clone or sprite to get at these variables. If you need to share this kind of information, ask and we can explain further.