Sorry, I hadn't seen the previous question. Regarding the classes, the plugin creates individual skill trees for each actor, meaning one tree for each character. You can duplicate the same tree for a swordsman for all swordsman characters. Even if the character changes class, they would retain the same tree. However, there are ways to condition some nodes to specific switches, so by changing the switch, you can completely alter the tree without affecting already acquired skills and other customizations.
Since the focus is on individual customization, it's not possible to assign the tree directly to the character's class, but rather to the character itself.