Help with characters inspired by celebrities

I’m writing a fictional book that is about the real world. In the book it involves characters inspired by real celebrities living and dead (mostly dead) and their stories but, painted in a negative light. I’m not copying these celebrities and their stories identically but, they will be similar for the sake of the book. I would like to copy them identically for the sake of the reader being able to tell who they are. I just wanted to know the legality’s of doing this. Could I be sued if it’s too similar? What can I can I not copy? Do my characters need to be mostly original? Is it a crime if there’s a close enough resemblance to the real people? & so on…