Good Morning
This goes quite a long way back but yes they are related.Here is the simple tree starting with their common Ancestors.
William Comins or Chillcott married Joan Downey 1702 at Witheridge
Children Elizabeth 1.1.1702,Thomas 31.1.1705,Thomas Cor C 1.8.1711,Elizabeth 13.2.1713,William 1716 ,Ancilla 1722 ,Sarah 1725 and Andrew Cor C 28.2.1727
Thomas m Mary Melluish 26.2.1745 Cruwys Morchard
son Thomas Melluish Comins bapt 8.3.1747 m Anne Crispen 29.11.1773 Nymet Rowland (PCC Will1815)
grandson Thomas bapt 8.1.1777 m.Elizabeth Deane 10.2.1810 Barnstaple (PCC Will 1850)
great grand daughter Mary bapt 7.10.1813 married Thomas Howell Stevens 29.11.1834
gt gt grd d Mary Ann Comins Stevens bapt 13.9.1837 St Pancras
On the other side
Andrew Cor c woolcomber m Mary Bidgood 13.11.1748 Witheridge
Thomas Comins bapt 24.10 .1764 married Joan Webber 2.2.1786
grandson William Comins Solicitor bapt 1.7.1789 married Mary Burgess widow at West Anstey 15.2.1822
great grandson William Willoughby Comins bapt 9.9.1826 marries Mary Ann Comins Stevens
They are something like 4th cousins once removed.
Of course I haven't included their siblings and burials etc ,but that does connect them all up.
Hope that hepls
Ciderdrinker