Are there any sources that the South wanted to free the slaves but the road block was what to do with them?I highly recommend Thomas Fleming's book "Disease in the Public Mind" that talks about the psychology of the reasons for the war. Some of it is certainly "plant/grow" but there was legit concern after John Brown that the abolition movement, which was getting increasingly violent, would lead to societal collapse in the South.
Between Nat Turner and the situation in Haiti Southerners were like "We'd like manumisson as well, but y'all have to help us figure out what to do with millions of uneducated people" because just releasing them was not an option, which is why Lincoln and most Yankees were in favor of back-to-Africa movements.
I think that eventually would’ve been the problem, but I don’t think we were to that point yet (or would’ve been in the following, say, decade.)