Yes, I am still researching the McGill line and would love to exchange info. with you. I'm excited to finally find someone else working on them!!
My line is a sister to your Wm. Caroll McGill. She was Elizabeth P. who married Jos. Riley Ward and moved to Wms. Co., Ill. from Benton Co., Tn.
I have a fairly complete family group sheet for Wm. Carroll and Louisa's family. Hopefully we can be of some help to each other.
Which one of Wm. Carroll children is your line?
Do you have any OLD pictures of the McGills?
Contact me at: firstname.lastname@example.org
Looking forward to hearing from you!