There were no bills or plans to abolish slavery in the south with the Confederacy was declared. They claimed it was about 'states rights' regarding the legality of slavery in new states, but in actuality it was because they had come to recognize the truth that even when not putting a presidential candidate on their ballots that candidate (Lincoln) could still win a Presidential Election even if no one in their states supported him. That was the proof that they were nigh powerless.
Remember that Lincoln wasn't really in favor of Abolition until well into the War, and the 7 States declared the Confederacy after Lincoln was elected but before he took office. It was all about economic and political power, and the Confederate states pretty much said 'if our votes don't matter, we are leaving'.