Parish records for Fermanagh are spotty and this early almost none existant on line.www.emeraldancestors.comwww.rootsireland.ie
There doesn't appear to be any Tithe records for Fermanagh which is used as a census substitute for 1823-1837.
Griffith Valuation for Fermanagh not till 1860. A lot of
years passed. At this time there are 489 McManus but only 1 Patrick McCollin: www.askaboutireland.ie
Patrick McCollin, Parish of Clones, Townland Drumswords,
Poor Law Union Clones, tenant of John Elliott
1b John McManus - house
2b Patrick McCollin - free hold - owns his own house - no value and no land.
A lots of the Mc and Mac were Scots background and came
with 'plantations' of farmers from Scotland.
The current British Telephone book for NI shows no McCollins (perhaps spelling) but 46 McManus and until you know where in Fermanagh impossible to pick out a few to write letters to.