Can an item be labeled pareve and dairy at the same time?

No and Yes.

If we use a truly technical definition of vegan, then these items should be kosher pareve (if they are kosher), not kosher dairy. Kosher dairy requires there to be some type of dairy ingredient, which should make a product vegetarian, not vegan (since vegan products lack dairy by definition). However, the "standards" of dairy non-presence in vegan certification and the minimal requirements of dairy presence in kosher "standards" have some overlap. (I.e. Imagine that the vegan standard is 10 ppm of dairy as a maximum and the kosher dairy standard is a minimum of 5 ppm dairy. Any amount 5 < x < 10 ppm will qualify under both standards.) Any amount of dairy in this overlap will be both vegan and kosher dairy.