Miss Thomas says "Dark or not, even Blind Lemon Jefferson could see something's wrong with this baby's eye." Blind Lemon Jefferson was an actual person! He was one of the most popular blues musicians of the 1920s. He died in 1929, but any musician active in the 1930s would have known him. Yes, he was blind, and he was born that way.
Bud continues to mention a tiny seed growing up into a mighty maple tree. His tiny idea that Herman E. Calloway is his father has grown into something he actually believes with all his heart. Here's a tiny seed (notice the blades of grass) and the mighty maple tree is could grow into (notice the tire swing):
In chapter 15 Bud is introduced to Grand Calloway Station which is named after Grand Central Station. It is the largest train station in the world and about 125,000 people go through it each day.
Finally, here are the creatures that Bud was worried might come out of the closet doors. Both Frankenstein and the Wolfman are from popular movies of the time.