My McWhinnie's start with Quinton McWhinnie b: 1682 New Cumnock
m: Mary Crichton (b 1684 N Cumnock) and had 9 children that I have note of.
You can get all the names on familysearch.org. My trail follows 4th son, James (bapt. 19 Feb 1725). He married Agnes McCrone and of his children, one of whom was Janet McWhinnie, my ancestor.
Janet married James Pearson & had 8 children. Child 5, Elizabeth married Archibald McWhinney, child 7, Elspeth Pearson married Archibald McKenzie and child 8 Mgt (Maggie) was my gt g/mo who married John Wilson, Tarbolton .
This is all straightforward and easily obtainable from familysearch.org however back to James Pearson & Janet McWhinnie, their eldest son Thomas married Margaret Hunter and of their children, their son Thomas married Margaret Logan in 1833 and 5th child was named Jessie McKenzie (McWhinnie) Pearson.
It is uncertain whether Jessie married, I doubt it as her 4 children all carry the surname, Pearson. I haven't done much work on the McWhinnie's but the new familysearch website has Quinton's tree as an Ancestral File so that would serve as a good guide for you. The change in Jessie's name shows the interchanging perhaps due to local dialect and the clerks spelling of what he heard. I can PM a copy of my tree if you like, just let me know.