That's a great list. How about some love for Virginia Lee Burton? She should be mentioned in the same breath as Beatrix Potter, Margaret Wise Brown and Jane Yolen.
A name rarely mentioned is Patricia Scarry, who illustrated much of her husband's earlier work, and she also wrote some including Good Night, Little Bear and The Bunny Book. That last one is one of my childhood favorites, and perhaps the earliest picture book example of a stay-at-home dad.
I don't think Lillian Hoban wrote any stories, but her Frances illustrations are all-time classics.