Headscratchers / The Jewel Kingdom

• It's established that Demetra is the oldest sister and Emily is the youngest, but what order do Roxanne and Sabrina fall in?
• We know that all the girls in the 2020 reprint are cousins, and that at least Roxanne is confirmed to be the king and queen's niece and not their daughter. But are all of them their nieces, or is one still their daughter? And what happened to the others' parents — did they all perish during the Sad Times?