I have a little more info on the Brockwells. It probably isn't going to help you out much, but your post got me thinking about the Brockwell geneology again, so I thought I'd capture some of the data I've managed to dig up.
From the 1900 Obion Co. TN Census: Theo's father was Robert (Robb). Mother Sarrah. I believe Sarrah's maiden name was Bizzle, but I'm not sure. Theo's siblings: Dave, Claude, Ada, George A.
From the 1880 Obion Co. TN Census: Theo's father: Isaac(born in VA); Isaac's wife: Emiline (unknown maiden name). Isaac's children: John M., William, James, Edward, Robert, Ada, Ida. Issac also apparently had a servant named Dunkin Bell or Bill Dunkin. Another person named Martha Luker was in his household, listed as a sister in-law or something like that.
From the 1870 Obion Co. TN Census: The writing is hard to deciper, but 38 year old I.(Isaac) R. (Robert) was married to Emiline. Children: Mary E., John M., William, James L., Edward. Martha Luker is also with them and is listed as a domestic servant (27 years old).
From the 1860 Obion Co. TN Census: Issac and Emiline's family: Isaac is listed as Isaac R.. He is 28, Emiline is 24.Children: Mary?(age 4), John, William. Martha Luker is also with them now.
From the 1850 Obion Co. TN Census: Edwin Brockwell, age 38, profession: Cooper, born in VA. Edwin's wife: Sarah, age 42, born in VA. Children: Robert (19)(born VA)(farmer), Lurana (sp?)(19)(born TN), William (14)(born TN), Isaac (13)(born TN).See posts by Charlie Hammet, because now some of these relationships confuse me. For example, Charlie says that Isaac was Edwins oldest son, but it looks like Robert was, unless Robert was Edwin's brother maybe???
From the 1840 Obion Co. TN Census: E. T. Brockwell (Edwin Thomas?) is listed as a "free white person" with the following demographics in his household: 2 male children under 6; 2 male children between 5 and 10; 1 male between 20 and 30 (I assume this is Edwin); one female 5-10; one female 20-30 (I assume this is Sarah).
From the 1830 Henry Co. TN Census: Edwin Brockwell: 3 members in total household. There is also a John Brockwell that I believe is Edwin's brother. 5 members in his household but it is hard to read the column headings.
From the 1820 Prince George, VA Census: There are 7 Brockwells that show up. Some of the names are hard to make out, but here's what they look like: John, James, John O., William, Jefor, "Littleborty"????, Joseph. My theory is that Edwin was John's younger brother and was not listed as a head of household in this census, and that John is the one that migrated to Henry Co. TN with Edwin. I'd love it if someone could confirm that.
From the 1810 Prince George, VA Census: 2 Brockwells show up: Can't read the writing, but possibly Joseph and John.