I am not connected to the Checkley Fernyhoughs that I know of, but I did look at the possibility of the family being connected to my missing Edward, whose oldest child was born in 1747. I know that your 4xg gf was not the right age, but wondered if the name ran in the family. Alas, no.
I have the IGI organised into a database, so that I can search it as I like. I agree that your family all appears in it, as do the siblings of Thomas:
Annbp 15 Oct 1711 Elizabethbp 17 Feb 1712 Williambp4 Jan 1714 Francesbp 31 Dec 1715 Johnbp 16 Sep 1718 Marybp 31 Jun 1720 Helenbp 15 apr 1722 Thomasbp 14 Jun 1724 (Edward's father) Janebp 23 Oct 1726 Adambp4 Oct 1730
I have not proved any of this, but from my wills index, I can trace a link between the Fernyhoughs of Checkley and those of Dilhorne, so it may be that Thomas's parents were Willian and Frances. William could have been baptised at Dilhorne on 5 Feb 1686.
I have not sorted out the information from any wills yet, but it looks as if William might have died between 6 July and 6 November 1730, but I am not sure. I shall let you know if I can find anything more definite in my records.