Just remembered these: https://www.goodreads.com/author/show/298438.Kerstin_Gier
Kerstin Gier’s Ruby Red trilogy. They are Young Adult, and young YA (only kissing and MAYBE an unbuttoned shirt, rather silly plot, main character acts very young, amazing best friend). I admit I LOVE them. And they have time travel! and Count St. Germain! Rakoczy! COSTUMES! Oh! the Costumes!
Terry: read them for the Costume Designer (whose name I can’t remember)because she is the best and see if Little Moore might like them.