When the War Between the States broke out, the loyalties of 3 states were in doubt, sort of. Lincoln's advisors were sure Maryland wanted to secede. That was militarily unacceptable so troops were quickly moved in. Missouri could have gone either way, depending on which side controled the armory. The Yankees won out. Virginia was badly split between the aristocratic, slave-owning piedmont and the western hills, where people were lucky to own a mule. Virginia was split. Texas is often considered southwestern, rather than southern. In fact, the Texas Rangers enlisted in the Confederate Cavary en mass, Praxitales Swan was a noted cavalry general, and one of the last battles, Tres Palmas, was fought in Texas. I think Florida was an official member of the Confederacy. If so, it's contribution was minimal, being ravaged by cholera, yellow fever, and hookworm.

As mentioned earlier, 'Dixie' is a generic term. It's exact definition depends on the sympathies of the user.