Charlie and Renee are Emmett’s in-laws. Renee accepted Emmett right away, Emmett even calls her Mom. Charlie took a lot longer to warm to Emmett, not trusting him for a long time with his daughter and blaming everything on him.
Carlisle and Esme are Jasper’s in-laws. Not mentioned in detail.
Emmett Sr. was Karen’s father-in-law. Not mentioned in detail, although in my mind, Karen never having any parents, her father-in-law meant a lot to her.