Placecard name question

Are you using the same names on the place cards as you used on the invitations?
For example I addressed an invitation to Mr. Joseph Smith, but I really know him as 'Joe'. Do I keep the placecard with Joseph?

Also, I have 2 sets of couples with the same names at different tables....the husband and last names are the same, and the wives names are different. How do I make sure they sit at the right table? I was thinking of including the wife's name?
i.e.
Mr. & Mrs John & Ann Smith
Mr. & Mrs John & Mary Smith

What to you think?

I am just putting Joe & Anne Smith, I am not goign to put the Mr& Mrs, like the invitation.