For the game were making we want to be able to disconnect bones in game - the forearm of our character will need to be removed and able to be replaceable is there a way to do that and how ? ( the characters forearm will be able to be replaced with different arm types so we need to be able to replace the forearm bone
Easier than it sounds and a better description of the actual game mechanics would help but from recognizing the duck what you are describing is nothing more than a different type of weapon. How many different arms though can make a difference on how you can do the setup.
Already explained how one can create a component character if what is needed is unique to a given player model.