Apostrophe usage in possessives

Mrs. Jones and her husband, Mr. Jones, and their three children are together called the Joneses.
Mrs. Jones's cat, Fluffy, has a bad habit of scratching the Joneses' couch.
The Joneses have another cat, Mr. Tibbles, who is better behaved.
The cats' litterbox is located in the bathroom near the children's playroom.

This exercise has been brought to you by the noble apostrophe.