The south was definitely not monolithic. Virginia seceded by a single vote majority, it could easily have gone the other way. At the 1860 census, 90% of the people in Virginia were not slave owners, and 7% of the people had only one.

You mention Eastern Tennessee, which actually seceded from Tennessee, and remained so until the late 20th century.

In Texas, the first vote for secession, after Sam Houston urging, decided to stay in the Union. It was only a few weeks later, when he was no longer present, that Texas decided to secede.

It is very nice to know there is a place in Alabama that bucked their state's character and stayed true to the Union, thank you for that additional bit of info.