Mike could possibly be friends with Chester.Chester hurts Mike the least and hates the other personalities more than Mike.
Vito is much yonger than Chester.Chester is annoyed at Vito in Backstabbers Ahoy when Vito talks while sleeping.Chester and Vito are seen talking talking to Mike about how they are seeing him.
In Backstabbers Ahoy Svetlana jumps of Mike's bed and lands on the floor and wakes up Chester who complains.
Manitoba and Chester have never talk each other or been seen together.
No personality has seen or talked to the evil personality.