Lucinda’s answer to “Hello Lucinda! I am eating up the seven sisters as fast as I eat up cake and it's as satisfying!! …” > Likes and Comments

If I may suggest. Maybe the 'rock' (pebble) sister. Since she is someone anyone is/could relying on. Like a rock in the sea (tower of strength). And she wasn't really flexible (like a hard rock) at first, liked living in a known environment :).
Thank you for your amazing books! Currently reading sun sister

How about the May Sister, since Maia means May?