Mahy's poem was rhythmically great, and the nonsense was a lot of fun. She never goes into the actual meaning of fandango, but just seems to enjoy the word. I could hear a lot of Edward Lear in this, but also it reminded me very much of Nancy Willard's "The Man in the Marmalade Hat."
Dunbar's illustrations were not a great complement, because they did way too much to set the tone for how to think about the poem. She is a good cartoon-style illustrator, but the mismatch to the poem made it difficult to appreciate. As with most poetry, I just wish it weren't illustrated. I think it would be a very good poem for a read-aloud and to learn to recite, but without the pictures would be better.