She is "half Jewish and half Christian". Ryan said so in the youtube video posted by AngelEyesVideos called: Ryan Newman - Red carpet of "Unaccompanied Minors"
No.
Judy Davis is Catholic. She dropped out of convent school at age 17 to join a rock band. She played a famous Jewish woman -- the young Golda Meir in the TV miniseries A Woman Called Golda.