Great stuff!

"Besides the above elements, do you have reason to believe that it was close to 1902?" I believe it was roughly 1902 because he said it was about 1900 and he also learned a song about the Roosevelt/Washington dinner, which was in late 1901, from Lee.

My view with Kennedy is that he obviously encountered a blues song and his relative inability to remember/understand it authentically is irrelevant to the fact that he encountered it, which is evidence of its presence in LA at the time. Single major chord throughout or absence of IV or use of I-V-I-I at the end shouldn't be concerns anyway as these were all found in folk blues.