Here are what I feel are the athletes' personalities and what BFDI, Inanimate Insanity character are they similar too.
Red is confident and smart most of the time. He is just so awesome. He is similar to Lightbulb from II and II2
Blue, on the other hand, can be considered a jerk. Just like Knife from II.
Green is always competitive and willing to do anything to win. This attitude of his lands him into serious trouble most of the time. He is similar to Snowball from BFDI
Purple and Pink can get mad when something goes wrong and annoy some contestants and that's why they are hated by viewers. They are easily considered as the Pencil and Match of the athletes.