Longer answer related to 2, 4 & 5.
I think its hard to tell for sure what the numbers mean. Was back for harvest in Oct, still had a week of corn before switching to bean. I'm usually on the combine for beans but was hauling corn to the feedlot. Basically its dump the semi on a big outdoor pad or into portable augers they have a crew that pile it up 3 locations prob 3 to 5 million bushelstotal, some big piles. In past the crew was Mexican this year different, I'm not sure. Usually you expect the head guy can speak English. This year pretty much all hand signals but one time he needed to communicate so spoke into phone and showed me the English, the words didn't make sense but I knew what he wanted. Now the question is were these guys year round with the feedlot or just a part season harvest ag crew which is a special visa. I'm sure they were noncitizens so how does it count? Guessing this might be #2 but it was all corn not really sorting.
Second example when I was visiting farms related to startup one of the big issues was labor especially truck drivers. Really difficult to find folks who don't have a dui or accident history. A couple infractions and you lose your CDL. One of the operations was hiring South African farm workers for fall operations, these guys could speak English. Wouldve been non citizens but temporary work visa. Prob cat #5.
Third example couple years before we moved had hail damage our area of town, bunch of folks need new roofs. Lot of outside roofing companies were knocking on doors. We went with one of the best local and a wrestling friend of mine. When they started the actual job I had a question, guy on site had to call the guy who spoke English to come over. Again good chance the crew local contracted were at least part or all non citizens but were they living in US year round or part time workers? #4