McFalls/McFaulls of Bushmills/Billy

Hi Please can anyone help me find a connection between two families as I have exhausted all records I can find online.  My husbands Ancestors is Daniel McFaull born circa 1848 in Ireland.  His parents are stated as James McFall and Eliza Wallace on all records.  After recent searches in Scottish records where Daniel married and died, I have found three brothers - Robert Faulds born circa 1847 married Eliza Smith.  George McFall born circa 1852 married Margaret Steen in Coleraine. Charles McFall married born circa 1859 married Catherine Kelly.  I have never found any records at all in Ireland of these births and all records I have found again have come from moves to Scotland.  Census records etc all state that the family were born in Bushmills.  I have found a death record of a James McFall in 1864 in Bushmills and have paid for a copy but it does not have the information that I need to make the connection.

DNA matches link my husband to several people who have a James McFall in their tree but they have him married to a Mary O'Kane/Keon/Kane.  They have the children of this marriage as William McFall born circa 1827 and married Mary Halliday. John McFall born circa 1832 and married Rachel Todd. Mary Anne McFall born circa 1834 and married to William Evage/Evans. James McFall born circa 1835 married to Margaret Stirling and then Elizabeth Keers.  Campbell McFall born circa 1843 and married Rose Mceag/McCaig.

The family have not found birth records either so again is estimated birth dates from other records.

It is all of our belief that James married twice - firstly to Mary and then to Eliza but we are struggling to prove this.  I have joined local family history societies and have access to certain church records online but although I can see a later generation in the area, it just does not go back far enough.

I would really like to find both of James marriage records to prove the connection and also Mary's death certificate.  The death certificate that I have for James does not mention a wife's name but does say he is married.  The death was reported by Daniel McFall.  Also the births of all the children would be amazing.  I suspect that there may be other children and also there is a question over whether Campbell is the child of James and Mary or James and Eliza because of the gap between the dates of the children's births. I also suspect that it is likely that James and Eliza had a daughter Eliza as a death I suspect may be Eliza Snr was reported by her daughter but have found no record of her confirming she is their child. 

If anyone could help it would be amazing as we have several families working together and no one can make the breakthrough.  I think maybe we need more local knowledge and no one who is researching sadly lives in Ireland. It has been suggested that the only way may be in local church records.  We have been trying to prove the link for months and are no closer so if anyone can make any suggestions it would be so appreciated. Many Thanks