I posted this so long ago and am now finally reading your reply. I have a copy of the 1880 census from a library in San Diego. It has all the names you have except they say Kathie, Frankie, Johnie and Willie.
My grandfather is Nicholas Adams b 24 Jan 1885. So our grandparents are brother/sister. I will ask my mom if she remembers an aunt Katherine and uncle Charles. You are her 1st cousin. Her name is Mary Charlene Snelson (Adams) she's 71 years old.
I just called called my mom. She says yes she remembers she had and aunt Katherine and Uncle Charles. She said they must have lived far away because she didn't know the cousins. She and her family remained in Kempton, IL. Nicholas married Jardena Wilhelmina Raab on 22 APR 1914. They had three children: Florence, Russell and (11 years later) Mary Charlene. Nicholas passed away on 16 NOV 1979 in Fairbury,Ford, IL. He was at a nursing home for just a short time. He was 94. Looks like he was the longest surviving brother.
Would you have any info on Nicholas's and Wilhelmina's parents. Here's what I have:
Nicholas's father was named Mathius Adam born in Prussia. The census said he was boarding with his son Nicholas's family. It says he was 82 in 1880 so that would make his birthdate 1798.
Mother was Wilhelmina Beaver. No dates or anything.
That's what I have. Looking forward to hearing from you.