A person can be brought in for questioning without being arrested, right?
It depends. If a person is forcibly restrained, they are under arrest. There is a sort of halfway situation that is known as "being detained". The courts have ruled that police can "detain" a person for a few minutes while they ask them questions. More that about 15 to 20 minutes is considered an arrest.
It does not really matter what the police call it. If a person is forcibly restrained for more than a few minutes, they are under arrest.
If they know they can leave, but voluntarily remain with the police while they are questioned, that is not an arrest.