"...would the War for Southern Independence have been fought if Slavery had not been involved?"

Do you mean would secession have occurred had slavery not existed in the US? Then no---no slavery, no secession.

"My position is that yes it would have. My reasoning is that the States Right issue of the south embodied far greater legal principal that just the ownership of slaves."

I agree that the principle or idea of states rights encompasses more than slavery. Many northerners during the nineteenth century also championed states rights at various times.

States rights as a principle was not something that generally stood by itself. It is abstract and only has real meaning when applied to real world interests. Like "freedom" or "independence," the term "states rights" does not really mean anything until placed into a certain context: "freedom" from what? "independence" for whom and why? a state's right of what?

Because principles only gain meaning when placed in real world contexts, we must identify what interests are involved.

When considering secession and the Civil War, we must ask why only slaveholding states championed states rights to the extreme. What interest or interests were these states trying to protect from the increasingly Northern-controlled federal government? The answer, when it comes down to it, is slavery.