Hassett of Brownstown, Westmeath

My Irish mtDNA ancestors are from Brownstown, Delvin, Co. Westmeath, Ireland.  From Catholic Irish Parish Records I have found a large Hassett (Hafsen, Hassan, Hassen, O hOsain) family in Brownstown of at least 3 generations.  This is what I have, all information is Clonmellon Parish, Counties Meath & Westmeath, Ireland:

Speculative 5x great-grandfather Hafsen/Hassen m. unknown
Speculative Children (information from Irish Parishes Register but not certain of exact relationships:
Bartholamew Hassen m. Mary parents of son Thomas Hassen b. before 7 Apr 1801 Nobber, Meath, Ireland
Peter Hassen d. 1829 Brownstown, Westmeath m. Ann McDermott, parents of Mary 1791, Judy 1798, Margaret "Maggy" 1803 Clonmellon Parish
My 4x great-grandparents John Hafsen/Hassen Sr? 1780 m. Eleanor McCormick c.1780

I find 2 illigimate births fathered by ~a~ John Hafsen but I don't have proof whether this is the same John Hafsen/Hassen
John Hafsen & Bridget Tolan parents of John Hafsen, Jan 1794, illegitimate
John Hafsen & Margaret Sheridan, parents of John Hafsen, 13 Dec 1795, illegitimate
John Hafsen & Ann Maguire, parents of Chris Hafsen, Sept 1789, illegitimate

My 4x great-grandparents:  John Hafsen m. Eleanor Macormick 16 Mar 1795 in Collinstown, Clonmellon Parish, Westmeath, Ireland.
Possible children:
Peter Hassen 1796
Phelim (Felix?) Hassen 1797-1870 m. Brigid Maguire (see Griffith's Valuation for Phelim)
Hubert Hassen 1799 m. Catherine Maguire parents of Patrick 1827, Judy 1829, John 1834, Hugh 1838, & Margaret 1841
John Hassen 1801-1805
Ann Hassen 1803
My 3x great-grandparents: John Hassen/Hassett Jr? 1805 Ire - 1881 NY, USA m. Catherine Battersby 1803 Co. Meath - 1871 NY, USA
Thomas Hassen 1808

Children of my 3x great-grandparents John Hassett m. Catherine Battersby
Eleanor "Ellen" Hassett 1836 Brownstown, Westmeath - 1891 NY, USA, never married
Honor Hassett 1837 Brownstown, Westmeath - unknown
My 2x great-grandparents Mary Hassett ABT 1839 Brownstown, Westmeath - 1918 NY, USA m. Matthew Moore 
John Hassett III 1842 Brownstown, Westmeath - 1919 NY, USA, never married
Catherine Hassett 1847 Brownstown, Westmeath - 1849 at sea
This family emigrated to the US in 1849. 

Also, in the 1850 federal census for Genesee County, NY, for the Hassett household, 3 additional young men are living with them, including Hugh Hassett age 13 (b.c.1837 Ire).  Hugh is found elsewhere in Genesee County, NY for many decades.

Mary Hassett m. Matthew Moore is the only child of this family to marry.
5 children were born to them: Charles, Jacob, William, Elizabeth, & Catherine "Kitty"

Regarding the surname Hassan, etc. We do know the surname of this family evolved to Hassett from the parish records.
According to Wikipedia:  "The surname Hassan in Ireland is one of the anglicized forms of Ó hOsáin. It is to be distinguished from Ó hOisín and Ó hOiseáin (see Hession and Hishon). In County Londonderry, where it is numerous, it is spelt Hassan, Hassen, Hasson, Hassin, and Hessin. In the Monaghan Hearth Money Rolls of 1663 it appears as O'Hassan. There was a Hasson of Wexford among the "principal gentlemen" of that county in 1598, but that family was no doubt of non-Gaelic stock and a John Hassan was an influential merchant in Wexford fifty years earlier."