As for putting the meat grinder in the freezer, I'd like to know if restaurants do that or not. Because I highly doubt it. Seems very silly.
Except that's not true. It's perfectly seasoned. Whenever you cook meat, especially if you're grilling it, you need to season well because half of your seasoning isn't going to remain on the meat.
1. Only true if there's copious amounts of oil to absorb the seasoning. Otherwise it might get absorbed by the rendered fat of the burger. Sometimes 50% or more of it gets lost, sometimes less.
2. It is better to underseason than overseason. If you overseason, you end up with an inedible salt mess. If you underseason, all it takes is a quick sprinkle before you eat it.
That being said, I think the picture in #6 looks perfectly fine. I'd use a dash more of pepper though.
I’d lose the pepper though. Each to their own, but I find that peppering just results in a burger that tastes of burned pepper.
It is not, for all the reasons listed. You get much better texture when everything is cold, because you are actually grinding/cutting the meat, rather than squeezing and smearing it.