FaceBook Group Question

Hey I know that if you have someone as a friend and you have a group you can add them into it they don’t even need to accept they are automatically in the group.

If I make a new FB account and give that new account Admin over the group, of that account were to add it’s friends would the same thing happen would they be put in the group automatically without accepting anything?

To add friends into a group using this method does the group have to be on public or can I have the group on private and still add friends into a group?