Montgomery is probably the only viable alternative.
The Confederate choice for Richmond was probably the best bet. The Confederacy was made with Virginia and could have been unmade without it. Norfolk and Richmond with the Tredegar Iron Works and most of the South's Industry were crucial for the Confederates, and appeasing Great Virginia was probably in the best interests of the Confederacy.
Unless they go with a compromise city somewhere in Southern Virginia, like Danville was OTL after Richmond fell, there is no real other choice.
New Orleans is too "unique", too Western, too exposed, and too urban.
Atlanta is too small, and before the war wasn't strategic enough to warrant being a capital.
Savannah and Charleston had declined in population and influence.