Hi James,
We might be on to something here!! (at last!!!!) We aren't too certain of our Sarah's age and birthdate, as it changes on the births of her children etc...so the date of your Patrick and Edward is well within the possibilities of them being either the brother or cousin of Sarah. Sarah and James Egan named their first child after Sarah's mother, Mary Ann, the second child was the first born son and named after James (and his father James,as was the Irish tradition). The next child was named Catherine...and I can find the marriage of a Catherine McVeigh from Armagh with a father Patrick and no mother's name listed,in 1854 to a William Sloan...but from there, I can't find them in any Census or records at all in both Ireland or England (perhaps they went to the US too???)..so this Catherine may have been a sister to Sarah...and as you have probably read, the next son was named 'Edward Arthur'..and there's your Edward's namesake!!
What will determine that we have the same family here is the name of your Edward's mother...if it was Mary Ann Hatherton, then bingo! Is there a death certificate for Edward anywhere??..this could tell you the name of his mother. Do you know anything else about Edward to the USA??
I'll see if I can find something about him on the net.
Many thanks for your contact James...let's hope we can finally put this story together!!
Best wishes
Rosie