Hi,
Don't know if there was a unit that was designated " Home Guard." There was a Unit of " Sullivan County Reserves " that probably performed the same duties. Go to Sullivan County Tennessee & the Civil War for a brief history of the unit taken from " Tennesseans and the Civil War " I had several soldiers from various branches of my family tree that served in Capt.J.F.Trevitt's mounted company. Have you ever read Daniel Ellis' diary ? I believe he gives his account of the " battle" with your ancestors in that book.
Good Luck,
Glenn