Did the southern states before the civil war broke out, talk about enslaving poor whites?

No. Slavery was a dying institution. European powers had begun aboloshing it and no longer traded with African tribes for slaves to bring overseas. Due to it's agricultural influence boosting the economy, the South was not yet ready to free current slaves but outside of children being born to parents that were BOTH slaves, there would be no additional peoples being submitted to it. Aside from endentured servants the only slaves used were African and in very rarely Native American. Really, the only talks in regards to slaves before the war was the internal debate in the Confederacy on whether to offer male slaves of military age their freedom for serving 1 year in the Confederate military.