If that tank in your previous post is indeed the accessory tank, then you have another tank for the front brakes. Which should be between your front wheels up above.
The valve you mention in the passenger wheel well is an air bleeder valve for moisture. We have one in the same spot on our 01. Once your coach is aired up, turn the handle, it should just release a short burst of air, then shut off. Then you move the handle back to the start position. By your position, I hope you're OK.
I can't help much on the E brake handle, never seen one like that. it looks like our battery disconnect switch lever. Where is that lever located, it's hard to tell from the picture?
From the air compressor you should have a small ping tank, then a wet tank, then a dry tank for the rear brakes on the passenger side. Then up front a tank for your front brakes and an accessory tank. Look up under the drive axle on both sides, you should see the wet tank on the driver side, then the dry tank on the curb side. The ping tank is harder to see, you will have to crawl, "Down Under" to see that one. It's only about 6" tall.
I can't help you with the air linkage, sorry!
Questions are free, it's when you go to fix them you'll see the bill!
