So is Sin.
In the Orient Town level intro, a screen can be seen in the top left with pictures of of Sin, Sol, and a few other characters from Overture. Keep an eye out for little things like this in the game. There might be more!
Fox McCloud is in the background of Carl’s level. And he is faaaaaaaaaaat!
Sort of lol’d when I realized what you were talking about.
They talk about Chipp in one of the tip sessions :bgrin:
I miss May!
Noel wears May’s hat in one of her Story endings, and also dresses like one of her crew.
I dunno if it counts but in Taokaka’s stage, there’s a sign that say 21 Turn Street. Reference perhaps to 21 Jump Street?
I thought it was a averaged sized knock off Faust in Orient Town.
well Valentine is also shown on that same billboard
also then there’s those really silly bits in Noel’s story 
I thought that was Barf from Spaceballs!