I am also researching the Duggans and have Robert Campbell in my tree. I tried to find him in the 1900 Census in Texas and in Tennessee under the names you listed but had no luck. Realizing that you did the legwork to find that, and I hope you don't mind me asking, could you tell me what ED and family number he is located in, in the Collin Co. census? I am drawing a blank. Also, I am trying to find the second marriage in the Tennessee marriage listings but am coming up blank. Do you know by chance what Mary Jane's last name was? Here's another curse at the 1890 census for being burned. It leaves so many gaps. You can reply here or to my e-mail at email@example.com
.. If I can help you I will try. I am researching the same lines as Vicki as she is a cousin to my boys. All of us want to get it right, of course.