Looking for McDonald/ Pickens family

I am looking for information about my gg grandmother  Ellen McDonald & gg grandfather Wiliam Pickens . Ellen's father was Peter McDonald. Ellen McDonald & William Pickens had a son also William. He was baptised in a Catholic church on 16 October 1853, in Annagh county Cavan sponsors were John McGuire & Mary McCabe. He is listed as illegitemate at his baptism. I have not been able to locate marriage records for Ellen or William in Ireland or Canada.

William Pickens & his son Wiiilam immigrated 13 July 1857, sailing from Liverpool on the Ellen Austin & landing in New York city with their final destination Canada. Ellen was not listed with them. They settled in Sheffield, Lennox Addington Ontario Canada. Canada West at the time. William Pickens & family settled on a farm beside Ellen's older brother John McDonald who was married to Margaret Ryan. John McDonald & Margaret Ryan settled in Canada prior to 1851.

In the census of 1841-1851, I have have found an Ellen McDonald, father- Peter McDonald, mother- Bridget Mary McDonald ilisted in Parish- Annagh, Barony- Lr Loughtee, Township- Clonosey. I would like to determine, if possible if this is my gg grandmother.

The only information I have about William Pickens is he was from the North, as stated by his daughter Mary in a 1930 census.

I have found some Pickens in the census but no William. In Griffith's valuation I have located a William, one in Tyrone & another in Antrim.I have also noticed several Pickens listed in county Cavan.

I would be grateful for any information which would help in my research.

JS