In real life you have to submit such a question to the SCTA on their website "clarification" form.
Now, in my opinion, all those you listed sure sound like mini-midi trucks.
As far as the El Camino's go, mine was huge, had the aerodynamics of a barn, and it had commercial plates on it (1968). I put my motorcycle in it. As soon as I see somebody stuff a 500 Yamaha inside a Civic, I'll start calling them coupes.
He's not asking the SCTA, he's asking us for our opinions and for those that do not know there has been a new rule initiated that would allow smaller car-based "trucks" like the ones he listed to run in the mid-mini truck class. Well, IMO, this does not follow the precedence the SCTA has already established by not letting full sized car-based "trucks" (El Camino, Ranchero, etc.) run as trucks. They have to run in the coupe/sedan classes and have had to for decades.
The full sized car-based trucks are significantly smaller in profile than a full sized truck of the same circa and I can confidently say that the mid-mini sized car-based trucks are also significantly smaller than normal mid-mini trucks. Does it make sense to anyone else that smaller mid/mini type car-based trucks be allowed to compete as trucks when full sized car-based trucks can't?
I was thinking that there is no area on the entry form for opinions, but be that as it may:
Opinion: From what I've seen in racing so far, a "truck" is whatever can get a timeslip in a truck class. It has nothing to do with whether it's a truck or not. A truck is something you use for work/pleasure to haul or tow things. They often have commercial registration. They have a tow hitch usually, and a bed that can carry at least 1000lb. And a diesel truck is one that is sold with a diesel drivetrain.
Currently in non-LSR diesel truck racing there is bit of debate about it. A "Street Pickup Truck" can now have glass body parts, full drag suspension, Lenco (or other non-street) transmission, and no effective cooling system. They aren't street legal, registered, or street driven. In fact, many need to be towed up to the start line. Putting a pickup body on a full race chassis is kinda like Pro Wrestling in my eyes. Good for show, but not the real thing.
But let's get real. WHO THE HECK RACES THEIR TOW VEHICLE??!!
It's a sideshow put on by the lunatic fringe. We are 1/2 racer, 1/2 hotrodder, and 1/2 daredevil, and 100% Redneck (hence the exemplary math skills).
What is a truck, and what ain't a truck, is defined by the race organization you compete in. The SCTA provided for truck classes, and for that I'm grateful. I will admit that I am confused by some of the rules, but I do my best to insure I'm compliant. And if I have questions, or if I desire a rule change, I use the proper channels to put forth a request.