No problem bud!

Steering angle sensor replacement is all done at the driver's footwell by the pedal. But you will need BMW software to calibrate.

The fluid might be from the front and or rear crankshaft seals if you really have no fluid loss anywhere else. But hopefully it's just scattered fluid from your minor leaks. I guess you can address the obviously leaking stuff then you can check if it those areas are still wet, hopefully not.

For the cooling system it looks good so far, I would also check the heater hoses that are sometimes easy to forget. I had a slow leak on the water distribution plate on the 4.6, those can fail also.

Squeaks sound like ball joints to me? Maybe have a helper steer back and forth while listening under the car? The sticking I cant think of a reason for at the moment.

Oh, and I meant just the rack end assembly which is the ball joint to the spindle and ball joint attached to the rack. The whole steering rack is expensive! I am looking at complete racks myself as I have a slight knocking noise traced to the inside of the racks of both the 4.6 and 3.0. Remans are almost $1000!

The transfer case fluid can be done DiY, no need to see the dealer except maybe get the fluid. Fluid is available online.

Hopefully you get the INPA/DIS working, it will pay for itself just getting your steering angle sensor working again.

Lastly, for the door panel plastic brackets, I had to repair mine and from what I see they use some sort of epoxy. The board looks too porous for glue to hold. I used an epoxy on mine and worked great, holding fine after a few door carrier replacements.

__________________
04 X5 3.0i auto
03 X5 4.6is