I believe that the William you're looking for was from a different family. William's obituary (from the Lewiston Daily Sun of 8 Mar. 1955) says that he was the son of James and Carrie House, born 9 Apr. 1895 in Lewiston.
Either his marriage record or death record says that his mother's maiden name was McCarty—I don't remember which. I am not able to find his birth record in Maine vital records, evidently because he was born out of wedlock.
William was living in Fayette in 1900 with his maternal grandparents, John and Emma McCarty, who had adopted him (Carrie was only 14 when he was born). His mother, Carrie, also lived in the home. In 1910 and 1920, William was living in Fayette with his mother. Carrie was living in Fayette as late as 1930, and still using the name "House," though it appears that she never married.
All I know of James House is that, according to William's census records, he was born in Maine.