I am also researching my McManus family from Kilmore, Co Cavan, beginning with John McManus born Kilmore, Co Cavan c 1746 whose military life has been fairly well documented in military archive records. He served in the 1st Regiment of Foot, fought at the Siege of Charlestown, South Carolina, was wounded and completed his military service at Fort George in the Royal Company of Invalids. He was 'demobbed' in Edinburgh in 1802. He married Margaret Ruddoch and had a son, John McManus, christened at Ardersier, nr Fort George on 9 September, 1799. My son, Duncan, was christened at the chapel at Fort George in 1970, some 171 years after his ancestor, John McManus. Duncan's name is inscribed on the Cradle Roll on the wall of Fort George chapel. The following information may be of some help with your McManus research.
John McManus christened Ardersier, 9 September 1799 to John McManus (soldier and shoemaker, born Kilmore, Co Cavan) and Margaret Ruddoch (Riddoch/Riddock) born Petty, Inverness-shire c 1780, lived in Elgin and had 11 children, several who sadly died young. I have visited their grave near the high altar of Elgin Cathedral where four McManus children are buried with their grandparents, John and Janet Murdoch.
John McManus (b 1799) died on 6 March, 1880 at Moray Union Poorhouse, Bishopsmill, Elgin.
His wife, Margaret Murdoch died 28 May, 1861 at 202 High Street, Elgin.
These are my ancestors, with their second youngest son, Alexander McManus, born Elgin 1837 being my great-great-grandfather. All of the McManus children were born in Elgin. Their surviving children all married and stayed in Scotland, some later moving to Edinburgh (as did Alexander McManus my great-great-grandfather).
I have a good deal of information on the McManus family of Moray that I would be happy to share with anyone researching this family.
Their long residency in Moray would discount their emigrating to Ireland.
They are on the 1851, 1851, and 1861 Scotland census and the baptism records for their children are on Scotlands People. Another excellent source of Moray and north Scotland historical records is Libindex (Moray).
John McManus, born Elgin, 1823 is on the 1841 Scotland census living with his family at Sievewrights (sp?) Close, Elgin. He was an Apprentice Printer on this census. I do not have any further information about him at this point in time but my research continues.