O'Connell (Connell) and Leahy or Murphy

I am searching for information on the William O'Connell family who possibly were from the Kilnamartyra area. Our records indicate William (born about 1769) married Catherine Murphy. However, a marriage record from 30 Nov 1805 for a William O'Connell of Gortnabigna and Catherine Leahy of Clonby Carthy seems very promising - largely because subsequent children and birthdates correspond to known children.

Baptismal records indicate William and Catherine (Leahy) of Gortnabigna had 5 children baptised: Catherine (1806), Daniel (1808), Margaret (1810), William (1813) and Ellen (1817). 

In September 1824, a W. Connell (age 60) and Cath. Connell and children (she age 50) along with John (26), Catherine (19), W. (18) arrived in Boston. They subsequently appear in Lincoln County, Maine where Catherine died in 1832 before moving on to Kentucky (where William died in 1841) and John and his family head to Illinois. It is known that Ellen (Mary Ellen) became a Catholic nun who distringuished herself in the U.S. Civil War. News accounts about her state she was from Limerick for all indications from her parents note the family was from Cork.

Any known connections to this family out there in IrelandXO land? Is it possible that Catherine's Leahy became McCarthy? 

Many thanks!

Kathleen Foley, Northfield, MN, USA (kathleen_foley@hotmail.com)