Thank you chempat for the leads and StanleysChesterton for the suggestion to advertise. Yes, Charles Yeo was Laura's brother, the son of Elias and Esther. If, as seems likely, Charles Yeo married Edith Williams, then the two families were even closer than I imagined with brother and sister marrying brother and sister. No wonder Caroline was buried in Thomas' grave. Charles died in India at age 20 in 1915. I wonder if he would have been in the military there?
When I was in Camborne last month, I felt that there must be descendants of Thomas Williams and Elias Yeo still in the area, but I had no way to find them in the short time I was there. I will research the newspapers mentioned by StanleysChesterton to see if there is a reporter interested in this story. If there is no interest, I will place an advertisement. Thank you so much for the help and ideas.