Matt, James L. McCombs (1858-1917)was married to Ruth Francis Taylor.James' parents were John & Matilda Lathem McCombs. John's parents were David & Sarah Sims McCombs, so they were James' grandparents.
James' middle name was Lattie.He is shown in the household of his parents, as Lattie, on the 1860 Census, but he is shown as a female (who knows why census workers recorded things as they did!). On the 1870 Census, he is shown as L. McCombs, male, age 12, in the household of his parents.
On the 1910 Census, James' father, John, is in the household with him.
The James M. McCombs that you mentioned being just above James L. on the 1910 Census would be his first cousin.