Now trying for some of your questions. First, this is John P. Usher the Lincoln cabinet member's family in the 1880 census--in Kansas, where the biography sites say he was mayor of Lawrence, KS, from 1879-81--so, it's the right John P. Usher. Note the servant "Annie" included in household, who is from overseas."Rutlandes" is misspelled—it would be, apparently, the only Rutlandes in the world. "Rutlands" or "Rutland" is more likely—but neither name is from Germany. It's an English name.
Household: Name Relation Marital Status Gender Race Age Birthplace Occupation Father's Birthplace Mother's Birthplace John P. USHER Self M Male W 64 NY Mayor And Lawyer CT CT Margrett USHER Wife M Female W 61 IN Keeping House IRE NJ Arthur USHER Son S Male W 33 IN At Home NY IN John P. USHER Son S Male W 30 IN At Home NY IN Samuel C. USHER Son S Male W 24 IN Lawyer NY IN Thomas DRISDOM Other S Male MU 39 MO Servent MO MO Martha CLARK Other W Female MU 50 TN Servent TN TN Annie RUTLANDES Other S Female W 16 GER Servent GER GER
Source Information: Census Place 2nd Ward, Lawrence, Douglas, Kansas
Same family, 30 years earlier:
Husband John Palmer Usher Birth:09 JAN 1816Brookfield, Madison, New York Marriage:26 JUN 1844 Death:13 APR 1889Lawrence, Douglas, Kansas Father:Nathaniel Usher Mother:Lucy Palmer
WifeMargaret Patterson Birth:About 1823Of, Terre Haute, Vigo, Indiana Christening: Marriage:26 JUN 1844 Father:Gen. Arthur Patterson
30 years later, the entire family is in Lawrence, Kansas, with 3 adult sons—ages 24, 30, and 33—single and living with their parents, in a house with 3 servants. One son is a lawyer. The other two, including John P. Jr., are "at home."
Now, your notes say that John P. Jr.married Mary A. Cumming in Cook Co. IL in 1879.
[Note: the second biog. site, above, for John P. Sr., the cabinet member, mentions that his wife Margaret at end of his service paid a visit to Illinois to visit her family. That's a possible connecting clue, and one of the reasons I include that link.]
So, does the John P. Jr. in Kansas, born 1849, go to Illinois to marry right around this census year? If that can be shown, then your line hooks up smoothly with the one above back to Nathaniel Usher, etc...
I see that info. on John P. Jr. is hard to come by because obscured by the blaze of his father's political fame and identical name. I tried the other names and kept watching for Illinois/Cook Co., but in your years of research you have perhaps found most of what there is; I found nothing...