Your oil filter mount is going to be part of the oil cooler mount like the lower image above. Plan to replace the oil cooler bolt rings and gaskets at the same time you replace the oil mount gasket. Rings and gaskets are still available from Toyota. You'll need a LARGE socket for the bolts...
If you click on my build thread in my signature line, you can see a post where I reference some green led's that I bought off of Amazon pretty cheap. And they have lasted and are much brighter.
That last image is from a right hand drive vehicle. USA version will be on the other side. it is a on/off and dial up type switch. I'm sure you could pull it and ohm test it. Before that, make sure the wiring behind it is tight and the white wire is going to ground. I've never had one fail...
Yes, like rebuilding the transfer case, replacing the pilot bearing and throw out bearing, re-surfacing the flywheel, replacing the clutch, and a new oil pan gasket if you go that route.
worry about the body rust and dents later. But, keep checking the classified section including the parting out section for a replacement tailgate and bumpers instead of trying to do body work there. Many other issues more important and body work is not going to fail you on a state...