how do I make a perm custom chester follower for my character?

[Samillennium]

So I want to make a follower for my character kind of like how crash bandicoot has...
They need to float just over the shoulder of the character, and I would like if they could be used as a Chester too...
coding is not really my strong suit so I wonder if anyone would be able to help me code this in?
I really only have 2 days but I've already drawn up and put my character in he just needs his little buddy.

Bonus if you can also help me figure out how to make this person change his form when he loses all sanity :/


Thank you so much ahead of time to anyone who can help me out!