Both St Christopher and St Barbara are Orthodox saints. The western St Christopher, the strong man who ferried people on his back over a river, is not found in Orthodox tradition. Christopher of Lycia suffered under the emperor Decius in about AD 250, and St Ambrose of Milan (340-397) wrote of the many thousands of pagans who were converted to Christianity by St Christopher.
Great-martyr Barbara is commemorated not only at her feastday, but also at the Prayer of Intercession at Vespers and Matins, in which a large number of important and prominent saints are invoked. The particular saints commemorated in this prayer varies between Orthodox jurisdictions, but, in my observation, St Barbara is always in the list, along with Sts George the Great Martyr and Panteleimon the Unmercenary.