Are the KDP keywords right for a children's or learning book?

Yes. The seven keywords follow the book: a kids book gets kids keywords (never relaxation or mindfulness), a mystery book "hidden picture coloring for kids" or "mystery mosaic color by number", and a color by code book its own keyword (for example "color by number addition for kids") with "math practice workbook for kids", "kindergarten learning activity book" or "preschool activity book ages 3-5". They change by themselves when you change the readers, the kinds of design or the code.