Who was Oscar's Dad?

For years now, I have been working on the life and family of Oscar Fitzallen Brown. We know quite a bit about him, really, but the one mystery that has plagued me is his father. If I can find his father, than I can find his mother: of that I am quite certain. But the father... who is this guy?  He's starting to get incredibly frustrating. Yesterday, I once again sent out an email plea for help from any family member that may be able to shed light on this particular issue. Here are the details...

Oscar was born in New York in 1832. Somewhere between the ages of 2 and 5 the family moved to Michigan to farm, and this is where he was raised. As a young man, he moved to Missouri and lived with his sister's family in Shelby County. Oscar joined the Union forces and fought nearly the entire length of the war, and then moved back to Shelby County, where he served for a time as Deputy Sheriff. Eventually, he claimed his homestead and settled in Colfax County, Nebraska. He married Frances E. Lawrence and had six children. He passed away in 1906 and is buried in Richland.

The candidates for father are...

1. William Brown: I am fairly certain that Oscar had a sister named Mary. She was born in 1817 in New York, and died in 1879. On Christmas Eve of 1835, she married Josiah H. Collins in Pittsfield, Washtenaw, Michigan, and they had five children; Henry, Charles, Mary Elizabeth, Josiah Jr. and William B. When Mary died, her death record states that her father was William Brown and her mother, Mary. It would make sense that she was named after her mother, and that her children carry some of the family names, also. 
2. Abraham Brown: This is the name given in Oscar's obituary as his father. No other evidence of an Abraham Brown can be found. 
3. Isaac C. Brown: He had at least two sons, Charles F. and Oscar F., and he lived in the same area of New York that we suspect the Brown family came from when they moved to Michigan. However, he never left New York (that we know of). Isaac left a will stating that his two sons (listed above) both residing in Colfax County, Nebraska, were to be left portions of his estate and Charles was the executor. I feel that this is the least likely answer at this time. Just something in my gut, I guess. 
4. Tolman (or Talmon or Talman) Brown: Born in 1791 in New York, he is listed as Oscar's father n the county books for Oscar and France's marriage. His wife was listed as Mary Morvie (1782-1836), once again supporting the idea that Mary was a family name. Talmon did own property in Washtenaw County, Michigan, beginning 1 Sep 1826. 

There is some speculation that William and Talmon are in fact the same man. There are branches of the family, through the Collins', that have notes indicating as such, and Mary (Brown) Collin's [see#1] headstone reads, "wife of Josiah, daughter of Talmon". 

Mary (Brown) Collins. Her headstone gives the best connection between William and Talmon Brown.

Headstone of Mary (Brown) Collins

Let's go back to the beginning for just a moment. I stated earlier that Oscar went to live with his sister's family in Missouri before the onset of the war. We learn about his sister through letter's in Oscar and Frances' pension file. Jennie Yoe and her husband Thomas Yoe wrote general letters to the pension board after Oscar's death in support of Frances receiving a widow's pension, stating that she was the only wife of Oscar, never remarried, and that they had known her for some time and thought her to be honest and upstanding. In the letter, Jennie states that she is the niece of Oscar, and if you back track their family, you find Jennie's mother, Harriet Brown, which you must conclude to be Oscar's sister.  One would think that I could look up her parents and be done with this whole issue... but her parents have disappeared, also. I cannot find any record of her life before her marriage. The one fact that does help in this search is that Harriet and Warren were married in Washentaw County, Michigan. All roads seem to lead us there. Washentaw County is a common factor for both William and Talmon, and I have not been able to connect the other two potential fathers, Abraham and Isaac, to Michigan at all. 

So it would seem that circumstantial evidence, or simply secondary information with indirect sources, have built a case that leans toward two assumptions: 1. William and Talmon are in fact the same person, and 2. William Talmon Brown is the father of Oscar F. Brown. How does this lead to frustration, you ask? Very simple in that it's not good enough to stand up to a systematic review in the genealogical community. I just simply don't have enough direct, first hand sources to prove or disprove any of the above. 

The search continues...