Welcome grinchyfell! Looks like Admin helped you out with a fresh start!
I figured you'd get some attention to your thread by mentioning the name of one of the previous owners. I don't think anyone here will associate you with that PO. I hope most everyone will keep in mind the spirit of this site, and offer you genuine help and advice.
The rear diff leaks and has been shaved for clearance. I would like to know if it sealed after the modification or not.
Done properly, shaving a 9" isn't a bad modification and should not leak. I suggest you get some degreaser/engine cleaner, clean off all the oil, then wait for it to reappear so you can confirm exactly where it's leaking. Then we can help.
Why is the rear air locker not hooked up to a switch and ran directly off the bottle?
Switches, wiring and solenoids are things that can fail. I don't own an ARB but run a selectable locker in the front and a Detroit in the back. I can see someone, for the sake of simplicity, deciding they will run an open differential on the street, and lock it up solid all the time when running off-road. Doesn't get much simpler than "open the valve" and "close the valve". If that doesn't work for you, the switch and solenoid aren't that expensive.
Is the tie rod end the wrong size on the drivers side or is the knuckle shot?
That''s going to be hard to tell, even with pictures. That will probably take some investigation on your part, like comparing the two sides. But there are repairs that can be done to the knuckle if it's worn. With a stock size tie-rod end, if the knuckle is worn, there are tapered bushings available that will work to repair the hole. Just ream out the hole a little bigger and install the bushing. Worst comes to worst, the hole can be brazed smaller, then reamed.
Why is the power steering line disconnected from the cooler?
As was suggesed, maybe there's an issue with the cooler, and bypassing the cooler was the simplest solution. Like bypassing a leaking heater core. Test the cooler for leaks and if it doesn't leak, hook it back up.
Any other info would help. I live in Oregon so I don't know a thing about the guy. Again I hope he is not held against me, I would just like some help if possible. Thanks, Steve 541-740-8080. I have the rig half ass for sale for $7,500.00 but I don't know if it is way to high or to low and I would like to keep it but I wanted to test the waters.
If you want to keep it, we can help get it fixed. If you want to sell it, post up some pictures and detailed discription and we can price it. It's up to you!