I'm not sure why so many are insisting on a cord reel. I added two ceiling drops when I did my garage workshop remodel. They are a great addition and easy to install.
You need the following:
1. metal electrical box
2. box cover with center knock-out
3. section of electrical cord
4. strain relief (sized to match your section of electrical cord). I got mine on Amazon Leviton L7503, $17
5. cord receptacle
I use hanging pendant outlets a lot. I have a couple hundred of them in the facilities I run. Your generalization in your list is incorrect as to what is legal (OSHA approved) and safe with what many electricians do. Let me tell you that electricians DO NOT really follow the rules and do what is safe when it comes to hanging pendants. I have learned this the long hard and almost very expensive way directly from OHSA inspections.
1. metal electrical box
OH HELL NO. Pendants are grabbed by hand all the time. What happens if your outlet shorts out to the box? Instant joy buzzer to whomever grabs it. This is a no no
EDIT when I first looked at your post the photos did not appear. I assumed that your pendant was the metal box. Just make sure you top box is fully anchored with over the joist mounting straps.
2. box cover with center knock-out
No box with knocks outs are allowed in any fashion. The box bust be formed with a boss connection as fully part of the box. Think what happens when, and it does happen, the nut inside the box holding the fitting comes free. You now have a metal item freely floating around in a box where people grab them and move them around. Sooner or later it will short out to the box or between the outlets causing a fire or shocking someone holding the box. Now something that is handled by hand is not allowed to have knock outs on it as they could release when someone grabs the box allowing a hand to enter the box and create a short and shock as well the possibility of cutting the person from a sharp edge.
EDIT for some reason when I first looked at your post the photos did not load. I see what you are using the plate for now and hat is proper.
3. section of electrical cord
Not just any cord is allowed. The cord must be of a design that allows stresses to be adsorbed in the casing and with internal strapping putting no strain onto the wires themselves.
4. strain relief (sized to match your section of electrical cord). I got mine on Amazon Leviton L7503, $17
Good here just put one on top and bottom.
5. cord receptacle
Good here also
Here are a couple photos that you may find helpful. (I hope this works)