The possessive form of the proper noun Cox is Cox's.
Example: This is Mr. Cox's book.
The singular possessive form for the proper noun Cox is Cox's.Example: Jeff Cox's brother is graduating this weekend.
The plural for the last name "Walls" is the Wallses.
No, Sarah is not a possessive noun. To make Sarah possessive, you must add an apostrophe s, making it Sarah's.
Doc Cox's birth name is Robert Cox.
rhodeses
Victor Cox's birth name is Victor Vern Cox.
Zaco Cox's birth name is Zac Alexander Cox.
Cruz Cox's birth name is Timothy Cruz Cox.
DeWayne Cox's birth name is De Wayne Cox.
Dick Cox's birth name is Elmer Joseph Cox.
Doran Cox's birth name is Cox, Doran Henry.
Eva Cox's birth name is Eva Maria Cox.