I gave up using an auger on my tractor. I have a NH skid steer with a 36" auger we plant trees with. I also have a 18" auger if we are doing post frame building or fence posts.
I might not be any help but on my DX 33 it's located under the dash on the right side. I have to remove the side panel on the right side where my knee would be. I know the 18 and the 33 are different beasts but that might be a place to look.
Fill the holes half way and then fill with water to help settle the soil. Next day add some more soil and fill with water. Continue until you are satisfied. Or being that you are putting a building over some of these holes you could fill in with pea gravel.
Sounds like you need something like guage wheels to limit the depth of penetration. You will want these to be adjustable for different soil conditions etc.
Back in the day my Dad and grandad would push big rocks onto what they called a mud sled and then drag that the where the wanted to go with it.
It also sounds like you need another tractor 🚜
You can probably find an old 6 row rear mount cultivator and cut it down to 2 rows if that is truly what you want. You would have a much better piece of equipment for a lot less money and you would have scrap to sell or inventory.
I had a 1466 sit for 5 years. Put new wiring harness on it and new batteries. Did nothing to the fuel in the tank. Fired up like it ran the day before.
When I service a tractor one thing I do is to adjust my top link about 10 turns each direction and I might add a little lubrication. I have many more tractors than I need. Some of which get very little use.
You can dump the fuel treatment right into the tank on your tractor, add fuel to stir it up, and run your tractor long enough to to get treated fuel through the filters and fuel pump. Never wait on fuel supplier to treat or blend fuel.
A IH 2000 loader is a very good loader that is built to be very stout. We had a 606 with a 2000 loader and it was a good match for that tractor. I have seen a 2000 mounted on everything from a 340 to an 806.