These are the different states in which a contact can be at:
Contacts who enrolled in the system and are scheduled to receive a message
Contacts who received an email or interacted via chat, but didn't reply back yet nor unsubscribed
On sequences that have Qualifying Questions, Engaged would be shown in the case where contacts replied back, without answering the qualifying question.
Exceed uses the Engaged template to ask the qualification questions and answer questions the contact might have asked.
Contacts who are qualified / have a meeting scheduled
Contacts who responded and the system needs a human's help to answer. These contacts are escalated to the manager associated with the sequence, for them to handle the reply manually.
Contacts who are no longer active or relevant: Bounced, Unsubscribed, Unresponsive (went through the entire sequence and didn't respond), Not Interested, Left the Company, etc.