Welcome to Rootschat. One of our members here is a relative of yours and has done extensive research on the Church family (I'll send them a message about this thread) but in the meantime-
William Church (c1761-14 Mar.1835) of Dullaghy House married Ann. He graduated Glasgow University 1779 and was agent for John Church of Oatlands in 1811. Children: Arthur (c1793), Elizabeth (c1786-1854), daughter (m. Henry Hunter), Jane (c1789-1857), Thomas (c1795-1840).
Arthur Church (c1793-8 May 1872) m.(1832) Elizabeth Crawford. Agent for James Church of Oatlands 1861. Two children: Hester & William (c1836-1908).
Hester Church (c1834-23 Sept.1919 Dullaghy House) m.(21 Apr.1853 Moyletragh Parish Church) William Johnston (d.21 Feb.1883), Drumsaragh.
1. Richard James Johnston, eldest son.
2. Susan Clinton Johnston (d.1902) m.(24 June 1889 Kilrea Parish Church) James Michael, grocer, Kilrea, and had: James Alexander (1890), Isabella Lennox (1892).
3. Arthur Church Johnston.
4. John Kennedy Johnston (c1853).
5. William Crawford Johnston (17 Sept.1864 Drumsaragh)- to N.Z. 1888.
6. Thomas Courtnay Johnston (5 Sept,1867).
7. Catherine Elizabeth Johnston (19 Mar.1869).
8. Joseph Clarke Johnston (8 Sept.1870), N.Z., m. his cousin Margaret Clarke Church.
9. Sarah Isabella Johnston (23 June 1874).