We have had many specific questions and concerns, including the appropriateness of joint locks on youngsters and the fact that there are many other known, demonstrated ways to teach children how to deal with bullies.
I for one will no longer be posting in this thread as it is clear you are either (1) simply seeking validation for what you are already planning to do, ignoring valid concerns that have been raised or (2) trolling.
There are a number of moves within the category of wrist-locks that place stress on the elbow and shoulder joints. The moves I have suggested are not intended to place much more than straight line stress on the elbow and shoulder. The wrist-lock being the main focal point of joint stress.
Controlling the partner by moving to avoid being hit with the free hand, or kicked, has been achieved, in my experience with youngsters, with a straight line force, through the elbow and shoulder.
The victim partner can keep pressure on the wrist, and using his/her hips, as the focal point, for keeping a pulling pressure, in pretty much a straight line, from the attacker's shoulder. The arm of the attacker does not have to be moved too far backward, to keep in a position of turning the attacker to the right, by keeping the attacker's right arm slightly behind the attacker, by moving the hips to keep an outward strain on the arm, from the wrist.
The idea is to keep ahold of the attacker's wrist, and by centrifical force, and by keeping the hips overbalanced against the attacker's resistance, to keep pressure pulling the attackers arm straight from the shoulder, or slightly behind, to keep out of reach. The victm leans back, to keep a straight force on the attacker's arm.
There may be more to protecting the attacking partner's elbow and shoulder, but so far, I have not found problems.