Hi Susan,
I am not sure of the tracks you have already trodden, but here are a few leads:
Tithe Applotment 1832:
Laheen, John Magee - possible father or family of Sam Magee b1835 http://titheapplotmentbooks.nationalarchives.ie/reels/tab//004625671/004625671_00178.pdf
Lots of possible info for Samuel Magee, Cavan here https://www.findmypast.co.uk/search/results?firstname=samuel&firstname_variants=true&lastname=magee&keywordsplace=cavan&keywordsplace_proximity=5&yearofbirth=1835&yearofbirth_offset=2&sourcecountry=ireland
Plus 2 articles referring to Samuel Magee of Laheen here https://search.findmypast.co.uk/search/irish-newspapers?date=1850-01-01&date_offsetdate=1899-12-31&firstname=samuel&lastname=magee&modifiedfacets=true&exactnames=true&exactkeywords=false&keywords=laheen
You can join findmypast for a month or more (if you are not already a member) - you can do a search of people and places in the newspapers separately, and it can be very productive.
Happy hunting,
Irene
