The men you have in mind are the so-called fire-eaters, Southern politicians with three names like Robert Barnwell Rhett, Laurence Massillon Keitt, William Lowndes Yancey, William Porcher Miles, John Anthony Quitman and others. Having little admiration for them, I confess to being loath to associate these men with the Southern cause. IMHO they schemed for more than a decade to manipulate Southern opinion in order to gain a position of power. Is that your area of interest?
David S. Heidler's Pulling the Temple Down: The Fire-Eaters and the Destruction of the Union, 1994, ISBN 0-8117-0634-6 includes a wonderful paragraph about the fire-eaters. Firm in purpose and will, they had no constituency until the crisis of 1860 arrived. I'll try to locate that later.
With regard to slavery having no connection to secession, let me digress in order to draw an analogy. In the pilot episode for AMC's "Mad Men", executives of the American Tobacco Company, the producer of Lucky Strike, have come to New York to develop a new marketing direction for their cigarettes. The Federal government has sued Brown & Williamson over health claims they made in the media, which cuts the ground from under any advertising campaign for Lucky Strike.
Representatives of the advertising firm Sterling-Cooper explain "that through manipulation of the mass media, the public is under the impression that your cigarettes are linked to... certain fatal diseases." The tobacco executive shoots back, "Manipulation of the media? Hell, that's what I pay you for!" Eventually it's decided that "any ad that brings up the concept of health and cigarettes together is just going to make people think of cancer."
The same is true for any attempt to claim secession had nothing to do with slavery. It's not the primary cause of secession or the war, but you cannot uncouple the two. Several years of reading Alabama newspapers printed from 1859 into 1861 and debates from the Alabama House and Senate has convinced me of what men from my home state thought. Their words are ungarnished, unfiltered and very explicit on slavery. I'll be glad to provide quotes and sources.
Eventually Don Draper conceives an easy way for his client to side-step the Federal government. Maybe you can do the same for secession and slavery!