Please... Do you really think any large number of Northerners were “abolitionists?” They were simply anti-Southern.
But they got their wishes: just visit inner-cities Baltimore, Chicago, Detroit, etc.
Yep. Many, many. Lewis Tappan, for example, had a large network in New York. They made up the bulk of the “Liberty” party. Don’t have a percentage, but it was far more than “anti-southern.”