To the first one:
True, however eventually the Missouri "Compromise" was really just an attempt to make the federal government in charge of the states without reason. IF the slaves weren't people (Which was how most people unfortunately viewed it back then) then popular soverignty or legalizing it everywhere would have been smarter. Since slaves were people, it should be illegal everywhere. But, it wasn't, and the North didn't care too, hence they were compromisers. In other areas, the South supported states rights and except for slavery I agreed with them.
To the Second thing: I used to live in Florida, and they weren't too uncommon there, however in NC when I was visiting I saw a lot of them. I laughed when I saw one in Pennsylvania. Never here in NY.