Some information which may be of interest –
There is no baptismal entry in the Ardboe RC register (dated from November 1827) for Mark Devlin, but it contains the following baptisms:
15 September 1831 – Catherine Devlin
6 October 1833 – Luke Devlin
11 May 1836 – Patrick Devlin
4 August 1839 – Joseph Devlin
The parents in each case are Eugenio Devlin and Maria Hanan/Hannan.
Invariably in the Ardboe registers the (partially Latinised) name “Eugenio” is Owen.
The address is the townland of Kinrush, in two instances the hamlet Clinba (part of Kinrush) is given as the address.
Devlin and Hannan/Hannon are strongly linked with Kinrush up to the present time.
I would surmise that these are siblings of Mark Devlin.
There is a baptism on 25 February 1855 for Eugene Devlin, of Mark Devlin and Mary Ann Quinn. Sponsors: Terence and Mary Quinn.
There are no other baptismal entries where Bridget Gillan, or any variation of the name, is the mother.
The only other mention of the surname is the baptism of Eleanor Hannon in 1831 where one of the sponsors was Michael Gillon.
Gillan/Gillen/Gillon does not appear in the 1826 tithes register for Ardboe, nor in the 1859 Griffith’s Valuation for Ardboe