LAMB Casting: Guess Who's Coming to Dinner?

Andrew here, with another film to cast for LAMB Casting. I decided I'd opt for a film with the lovely Katharine Hepburn who readers of my blog would know that I adore. We've been casting a number of youthful roles recently, so we're turning to the mature this time re-casting the seven principals of the film (four of whom were Oscar nominated).

So, it's your job to recast the following:
Matt Drayton (original played by Spencer Tracy)
Christina Drayton (original played by Katharine Hepburn)
John Prentice (originally played by Sidney Poitier)
Joanna Drayton (originally by Katharine Houghton)
Monsignor Ryan (original played by Cecil Kellaway)
Mr. Prentice (originally played by Roy E. Glenn)
Mrs. Prentice (originally played by Beah Richards)

and for kicks you can recast Tillie, the maid, originally played by Isabel Sanford.
 
Send your choices to me at dangerous.liaison231(at)yahoo.com. Who do you have in mind to step into these legendary shoes?