Yeah the Mikagura sisters knew Kagura (child form) and always played with them as kids. When their village got attacked by Yoma, the Mikagura sisters were surprised by how easily Kagura defeated them. And I think that was the last they saw of her then
By SK7, they'll likely reconnect with each other and become a team
I think they used Jasmine since she was the main priestess (as well as former Kagura) who was in charge of the Festival , and for Ryoki the universe where they were in didn't let souls go on until their loved ones had no more regrets (same went for Miyabi with her mother and the Gessen girls with their grandfather) so Ryobi and Ryona (more so Ryobi) had to figure that out