Let's unpack these one at a time. Yes, a significant percentage of the total population were slaves. Yet only a small percentage of the White Southern population owned them. Of those who did, half of them owned fewer than 5. So we are really talking about maybe 10% of families who were the really large plantation owners. For the VAST majority of White Southerners, slavery was not "integral". They didn't own any. Their livelihood hardly depended on something they didn't have.
Next, manufactured goods wouldn't be "marginally" more expensive. They would be massively more expensive. The Morrill Tariff TRIPLED tariff rates. Northern manufacturers would of course take the opportunity to jack their prices way up too. I notice you did not even address the fact that the Tariff of Abomination cut cotton sales in half when it was implemented AND lowered the price of cotton. So Southerners who had seen this all before, could expect not just higher prices for the things they needed to buy but also significantly less money for what they produced. They would be hurt in both ways, not just one. This was not speculative to them. They had lived it a generation earlier.
Or that with the liberation of the slaves, a third of the South’s population, would become hungry, homeless, without work, and free to roam and settle where they liked and do as they liked? And, as in Haiti, many of the freed slaves could be expected to be angry and vengeful toward their former owners and whites in general.
What liberation? There was no prospect of anybody imposing abolition. It was not constitutional and moreover, there was hardly any political support for it anywhere. *IF* it ever came, it would have had to have been on the same terms slavery was ended in the Northern states, the British Empire and various European colonial empires which is via a compensated emancipation scheme.....and that is for the relatively small minority of White Southerners who actually owned slaves.
Under emancipation, the former slaves would also get the right to vote and their numbers would determine the officials, laws, and policies in a great many Southern states and communities. That would be the end of white rule in those areas.
Where are you getting this from? Emancipation does not equal full civil equality much less the right to vote. The Northern states at the time had "Black Codes" under which there was strict segregation, Blacks could not sign contracts, serve as jurors, vote, etc. Even in states where it was technically legal for them to vote, few of them were foolish enough to actually try to do so. They would be violently attacked by White mobs if they tried - and they knew it. The Jim Crow laws enacted in the Southern States after the Occupation were based on the Northern Black Codes.
For many Southerners, the continuation of slavery was essential to a safe and civilized public order.
But for the vast majority who did not own any slaves, it was not.
Even for non-slaveholders, emancipation carried the certainty of not just major social and economic upheaval but also a risk of violence and chaos at the hands of newly free former slaves.
Again, you ASSUME emancipation automatically equaled full civil equality. It most certainly did not. Blacks in the North did not enjoy civil equality and were barred in many cases from owning guns for example.
As it was, the South after the Civil War experienced many such ills. The result was the formation of the Klan and the creation of Jim Crow and disenfranchisement to keep blacks separate and under control.
The South after the Occupation is a different thing. After the corrupt carpetbagger governments robbed the Southern states blind - invariably put and kept in office by Blacks after the vast majority of White Southerners had been disenfranchised - the White population was then deeply embittered. At that point they enacted Jim Crow laws modeled after the Northern Black Codes. At that point, they adopted segregation which had previously been a Northern rather than a Southern practice. The Klan arose due to the corruption and violence initiated by the "Loyal Leagues" and other such organizations as well as the massive corruption of the carpetbagger governments which often dispossessed people of their land.
Due to such calculations, most Southern whites who did not own slaves nevertheless wanted slavery to continue. That accounts for their support for secession, not tariffs.
There was no such calculation because there was simply no support for emancipation prior to secession nor was there a means to accomplish it except voluntarily via some form of compensated emancipation scheme AND emancipation did not mean civil equality. What accounted for support for secession in the original seceding states was the desire for Independence so as to set their own economic policies and stop being treated as cash cows by the Northern states. What accounted for secession in the Upper South was Lincoln starting a war and ordering them to provide troops to impose a government upon other states that did not consent to it.
(1) The Morrill Tariff did not pass until the South seceded. To blame it for secession is contrary to facts. In addition, the Morrill Tariff raised effective rates by 70%, which was less than a doubling, not a tripling.
(2) Reflecting growing abolitionist sentiment in the North and Midwest, The Republican Party was dedicated to putting slavery on the path to extinction by preventing its expansion to additional states and cordoning off slave states with free states. This platform alarmed the South even as it helped lead to Lincoln’s election in 1860, which then triggered secession.