Yes, they are.
The singing voice of Pablo is played by Sean Curley The season 1 speaking voice of Pablo is played by Zach Tyler Eisen The seasons 2-3 speaking voice of Pablo is played by Jake Goldberg The dancing of Pablo is played by Tasha Cooper
Catherine had 3 different voice actresses in Arthur. Patricia Rodrigues was her first voice actress (Rodrigues also voiced Sue elen) from season 1 to season 7. In season Alexina Cowan replaced Rodrigues as the voice for Catherine until season 15. In season 16 Robyn Thaler hickey now voices Catherine and so on. Btw Catherine is Francine Frensky's older sister.
A fisherman in the Season 2|Episode 12, Fifteen Minutes of Shame&The Black Knight from the Season 3|Episode 9, Mr. Saturday Knight
Karley Scott Collins, Ciara Bravo, and Charlie Bright.
Cody Cameron.
Dana Snyder.
Harrison Fahn.
Melissa Sturm.
Ciara Bravo.
Cody Cameron.
Matthew W. Taylor.
Karley Scott Collins.
Matthew J. Munn.
Matthew J. Munn.
Matthew W. Taylor.
2006 (Open Season), 2008 (Open Season 2), and 2010 (Open Season 3).