May several people register with the same phone number/e-mail address?
No. You cannot register multiple users with the same phone number or e-mail address, as this is used for logging in as well as identification. Each person is required to have unique contact points if they are added with these.
If a child is not old enough to respond themselves, you do not need to add a contact point next to their name, only on the guardians.
If a member has been added as a child/youth member (without a contact point, only guardians) but are now old enough to respond themselves, the administrator has to find the member in the group member list and add the childs contact point next to their name. The child will then receive a group invite and both the child and the guardians will be able to respond on behalf of the child.