Force the leg bone too hard by stretching too much you think it makes the leg grow and the person gets taller?

LOL, no.  Flexibility is good to maintain,  though. 

Nope. Bone ONLY grows when there are growth plates with living bone cells in place. Once they close, bone doesnt grow at all. Stretching doesnt make bone longer, only works the muscles and their attachments.

No. You're not "stretching" the bone itself, just the muscles and ligaments attached to it.

I don't think so.  It might work to put tension on a living bone and stretch it slowly over a long time.  But in the meanwhile you're doing damage to the joints.

I knew a guy who had polio as a kid and as a result one of his legs was about half an inch longer than the other.  Rather than lengthen the short one, it was easier to shorten the long one by cutting a piece out of the bone.