Unless there was a design change, that air stone should be aligned from left->right in the bottom center of reservoir (resting on the floor) as opposed to being stood up vertically like that. The bubbles should be emerging directly beneath the cocopod if I’m not mistaken - it’s usually glued there.
As for the plastic shield, have heard of one or two others not receiving one. I’d wonder if the unit wasn’t fully assembled if it’s missing the glue and the shield?
Can you turn your #5 bottle by 90° so we can see into it, perhaps the hose is suctioned against the inner wall of the bottle or simply not reaching? Also peek down inbetween the reservoir and that front faceplate behind the bottles, are the hoses plugged in on the pump that feeds the #5 bottle?