Yes, you can. As long as one finger is "pressing hard-ish" a second finger can command the drag position, but if the finger that is pressing (you do not need to press very hard to trigger a click) is not the one that is also moving, then you will have issues when also scrolling with two other fingers, because at that point you have 4 fingers touching the trackpad, and by default you get anoter gesture registered (probably a zoom out to see all the windows in the workspace, called "expose"). If the fingers touching the trackpad are "only" three, you can drag and scroll, with the window that receives the scroll being the one under the pointer/item being dragged.