The original "Loonette" is still alive. The original actress' name is Alyson Court. She was replaced in 2006 (one season) by Ramona Gilmour-Darling. I have googled it and they don't give a reason for her leaving, but her husband died in 2005, so you can see how her leaving might make sense. You can look her up on IMDB, where it lists a lot of voice work and some Canadian TV.
No, his name is Fred Stinson and he's actually married to the co-founder of Dyeversion (a Canadian-based yarn company)
Johnny Couch died in 1975.
William Couch died in 1890.
Lionel Couch died in 1989, in UK.
It is not very likely that a prisoner will ever become a couch potato and die.
Orville Couch died on 2002-05-26.
Carl J. Couch died in 1994.
William Terry Couch died in 1989.
C. P. Couch died in 1955.
Jonathan Couch died on 1870-04-13.
Ben Couch died on 1996-06-03.
Mabel Quiller-Couch died in 1924.