I'm also looking up Campbells from the Cavan area, specifically Bailieborough. My Henry Campbell, born in 1801, was my great, great, great-grandfather. His son, Henry, was born in 1836. I wonder if they're the same ones you mentioned.
Anyway, the rest of the family included Henry's wife, Mary (?), born 1806; daughter Mary, 1839; and sons, James, 1841, and William, 1843. William was born in Liverpool, England, after the family moved there, no doubt in an effort to escape starvation like so many others.
My grandfather, Bartholomew James Campbell, was born in Liverpool in 1898, and came over to America in 1918 as a ship's crew member.
His father, Patrick, was born in 1864, and was the son of the first James, born in Cavan. Patrick had sisters, Julia, 1862; Catherine, 1871; Sara Ann, 1876; Alice, 1880, and brother, Bartholomew, 1878 [whom my grandfather was named after]. His wife was Catherine (?), born in 1844.
Phew!!! That was a mouthful. Anyway, there are some similarities between your Henry's and mine. Could be we're related? I'm still working on finding out who the wives were and who the girls married.