Yup, that looks ok. The only thing I would mention is that the outline is probably better since it defines the boarder of the slot better. The engineers will follow it so that the slot does not extend past the center of this line. If the shape is filled, then there is room for doubt.
Regarding the other point, if there is both a drill hole and a milling slot overlapping on the same point, then the CAM engineers may be unsure as to which one you want them to follow. Drill or Mill? So, if you remove the drill holes from the drill (44) and hole (45) layers then this should remove the holes from the Gerber files. The pad can be left alone, there’s no problem with that.