The fair Coane has furnished the following instances from the 1641 Depositions:
1643: Nature of Deposition: Multiple Killing, Robbery in Donegall
Manus Oge Magoan was one of 143 Rebel soldiers named by Thomas Poe in his deposition.
1642: Nature of Deposition: Captivity, Robbery, Words in County Fermanagh
Shane McOwen was named as one of those who threatened Elizebeth Moore and her husband
and held her husband prisoner that they would be taken away unless we departed the
land and alledging the land was theirs and theire fathers and with Skines, and Pitchforkes and threatened to take away our lives.
The actual depositions are quite graphic and show the great stress that both the native Ulstermen and the transplanted Scots lived under in those perilous times.
The form of Mag rather than Mac grows stronger as you move farther north in Ulster and so I believe that Magoan could also be rendered as MacOwan or MacCowan.