Time ran out, and here's the illustration I submitted for the exercise:
To do it again, I might shorten Caterina's torso to make her feel younger and more playful, and I might paint the entire scene more loosely. However, I like them as mockingbirds, and am pleased with Leo's inquisitive interest, Caterina's list making and worrying, and the way she dreams of her party, as well as the unscripted cat.
Now I'm ready to get a copy of Kono's book to see how she imagined this scene, and I look forward to seeing how other illustrators tackled the assignment.
Sometimes it's fun to imagine things in new ways.
There are so many ways to portray similar things, and words can
create a different picture and perception for each person.