[donut]

While your flipping wheels, take a close look at the calipers. You said the brake fluid dropped. Why? If all the air was bled out and there are no leaks, it should remain constant. If it starts shaking, pull over and see if one wheel is quite a bit warmer than the others.
You said tie rods look good and ball joints new, wheel bearings new. Did caster ever get set?

I just browsed your build thread, obviously this isn't a stock, untouched pick-up.