There is no such API to get the real-time data of the participants attending the meeting.
However, you can get attendee list of events, please make sure that attendees are added to live event while creating it.
Here is the API that returns attendees of live event. You can see attendee list in response.
Event is different from Call, If you want to use call API you first need to get call ID.
You can this API to get Call id, then use the id in subsequent api's you mentioned.
Additionally,
[Post] sent request to this API (https://graph.microsoft.com/v1.0/me/events) to create an Event.
Request:
{"subject":"Let's go for lunch","body":{"contentType":"HTML","content":"Does noon work for you?"},"start":{"dateTime":"2017-04-15T12:00:00","timeZone":"Pacific Standard Time"},"end":{"dateTime":"2017-04-15T14:00:00","timeZone":"Pacific Standard Time"},"location":{"displayName":"Harry's Bar"},"attendees":[{"emailAddress":{"address":"first email address","name":"firstName"},"type":"required"},{"emailAddress":{"address":"{secound email address}","name":"{secound name}"},"type":"required"}],"allowNewTimeProposals":true,"transactionId":"7E163156-7762-4BEB-A1C6-729EA81755B8"}
Once, event is created use ListEvents API [Get] request to list my event which also returned attendees to the event.