Can anyone confirm which are the investigators?

So far:

Luke Robinson
Daisy Walker
Minh Thi Phan
Roland Banks

Are there 8 in total? Are these the missing 4? Or there is any surprise?
Lola Hayes
George Barnaby
Zoey Samaras
Hank Samson

Lola and Hank have been confirmed: https://www.fantasyflightgames.com/en/news/2017/1/18/dark-waters-and-darker-threats/