Amazon Prime Video has greenlit “ Reality Retreat ” (working title), a new series that stars major characters from other reality TV franchises as they attend “a high-stakes wellness retreat designed to challenge their identities, relationships, and personal growth.” The cast includes “Real Housewives” alumni Kenya Moore, Margaret Josephs and Kim Zolciak; former “Selling Sunset” star Christine Quinn; Brittany Cartwright from “Vanderpump Rules” and “The Valley”; Tamar Braxton, the singer-songwriter also known for “Braxton Family Values” and other reality series; former “Bachelorette” stars Kaitlyn Bristowe and Jenn Tran; mother and daughter Julie and Savannah Chrisley from “Chrisley Knows Best” and its spinoffs; and Hilaria Baldwin , wife of Alec Baldwin and star of “The Baldwins,” who also competed on “Dancing With the Stars.”   The official description for “Reality Retreat” reads, “Set in a tropical location, the series follows a group of women whose lives in the spotlight have made them icons,…