A religious tradition
The Seven Sleepers story describes believers taking refuge during persecution and awakening after a very long sleep. Treat it as a tradition with different versions, rather than archaeological proof of the event.
The Ephesus landscape
The associated cave area lies near the ancient city around Mount Pion. It belongs to a wider Christian heritage landscape with the Basilica of St John and House of the Virgin Mary.
Clarify the additional stop
Ask whether the area can be added and what is accessible. Do not infer cave entry or a devotional service from a general Ephesus visit.