Hello:
This board is for general problems/questions about US census entries. You would probably get more help by posting on a surname board (Willis) or a location board -- county.
I did look quickly at your tree because your query was not specific enough as to date and place. I suggest that you work on Ben Willis, his wife/wives and children as thoroughly as you can before you attempt to identify his parents. For example, I noticed that you showed your Ben Willis buried in Muscogee County, GA in 1949. I have serious doubts that this is your man. The Ben Willis who lived in Muscogee County had married an Annie/Nannie Watters? there in 1891 and lived there the rest of his life as best I can tell.
The Ben Willis of Scott County, Missouri was born in Missouri and both parents were born in Kentucky. His wife Victoria had been married previously. Alma was her daughter, but not Ben's. Benjamin F. Willis married MRS. Victoria Watson in Scott Co. MO in 1903. By 1920, Victoria was married to a Charley/Charles Gregory and living in Cape Girardeau Co. David, Jackson and Alma (divorced) were with them. David may have been the one who married Stella May King in Scott Co. in 1924.
I have not gone any further on this family at this time. I suggest that you work on locating and attaching all possible records for this family before trying to proceed back further. The only record you had attached for Ben (the 1910 census) did not have a middle initial, so the "H" may be wrong. This could send you up the wrong family tree entirely.
Good luck with your search
Sharon