Those actors are:
Yuko Hara as JunJun
Reina Ueda as CereCere
Sumire Morohoshi as PallaPalla
Rie Takahashi as VesVes
Sailor Moon fans will remember that the Amazoness Quartet are the most powerful followers of Queen Nehellenia, and possess orbs that keep them in a state of eternal childhood. Sounds nice!
Previously announced cast members include the cast from the Sailor Moon Crystal anime series, plus:
Shouta Aoi as Fish Eye
Satoshi Hino as Tiger’s Eye
Toshiyuki Toyonaga as Hawk’s Eye
The first film was initially set for September, but due to COVID-19, it’ll now open on January 8, 2021. The second film will open shortly thereafter, on February 11.
The films continue the story of Sailor Moon Crystal, which Viz describes like so:
Based on Naoko Takeuchi’s megahit graphic novel series, Sailor Moon Crystal retells the origins of Sailor Moon, the kindhearted crybaby destined to protect the world from dark forces. When the evil Queen Metalia and her Dark Kingdom threatens Earth, Sailor Moon and her fellow Sailor Guardians must find the only power capable of vanquishing this ancient evil – The Legendary Silver Crystal! But a mysterious man calling himself Tuxedo Mask is also after this sacred treasure. What is his connection to the Sailor Moon? And will the Sailor Guardians be able to find the Silver Crystal in time before the world falls into eternal darkness?