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I think your Houten/Houton families lived in Carthage townland in Culdaff civil parish. There were six Houten families in the 1901 census and one Houton family. The one Houton family has the Grace and James you mentioned but no William.In the 1911 census I found a William Houton age 15 visiting the Patrick Bradley family. This William was born in Scotland. All the families in the 1911 census were Houton.