The Cheinnselaig/Kinsellagh/Kinsellough/Kincheloesurname originates in Ireland in the old Kingdom of Leinster (Southeast Ireland). The name in Petty's 1659 census is prominent in Counties Carlow, Wexford, Kildare, and Queens (now Leix). None show up in Cork.
Was Cornelius Scottish? No evidence of that at all. Was he English? Extremely unlikely, since his surname family & their allies were strongly anti-English in the years just before Cornelius appears in America (Virginia 1693). If you know Irish/English history for that period, you know that Irish traditionals were at war with the English in the mid-1600s and again when James II fought William of Orange. It is almost unthinkable that a member of a traditional noble Irish family would have been allied with the English at that time. We know that Kinsellaghs (and their brother sept, the Kavanaughs) fought against William and the English Protestants.
Documentary & circumstantial evidence says clearly that Cornelius was an Irishman. Let's keep looking there. If any Kincheloes or Kinsellas want information on family in Ireland in the mid-1600s, contact me. I have some names & places where they owned land. One of these could have been Cornelius' father.