Hi Kimberly, You didn't include any dates, or approximate dates, for any of the people in your query, so I went looking at census records in Hill Co, TX.You didn't mention your family was mulatto, that would help explain some of your problem in your searching.
You also said Willis and Lucinda had 11 "siblings", I think you meant to say ll children. On the 1910 census Lucinda shows she had 9 children, with 9 living.I count 8 still at home on that census, (one obviously has married and left home) and by 1920 there are 2 more, that would make 11.I do not see 2 yr old Geneva on the 1920 census, maybe she is the one that died "young."
I looked at census in Franklin Co, TN and do not see a match there.What is your source that says they came from Franklin Co, TN?
I understand Ancestry.com now has an everyname index to the 1870 census.If your local Family History Center is online, they will have a subscription to Ancestry.com, you might try looking for Willis on that in TN.
Since Willis and Lucinda are on the 1920 census, they are will into the time period TX kept vital records.Do you know when Willis and Lucinda died?You can obtain a copy of their death certificates, which should show the respective set of parents for each.