There is a listing for a Mary Ann Leonard age 17 in Scipio, Meigs Co in the 1850 Census. That Census was taken in Sept and Mary Ann would have been only 15. She also alone and staying with Mahew family. It appears from the listing she’s the oldest child in that household. All of the other children are over age 11 and share the father’s name. He’s a broommaker. This could easily be Cyrus Leonard’s sister. or a relative or wife of another Leonard family member.