Insted of “Join Que”, I think something along the lines of “Get in Line” would be more understandable for students.
Per the 30 second wait time, I think that is enough time, but I think the change from waiting to “start pass” should be even more obvious. Maybe have the color of the pass faded or grey, and then light up to the original color when it is ready to go active. (hope that makes sense) It’s been my experience that there needs to be a very obvious difference or teenagers won’t notice.
On Kiosk, I would not want kids waiting at the front of the room. Pending on how the teacher had the device positioned, the color change of the pass mentioned above may help with that.