I don't really know, but you made no mention of checking
for warped rotors. I suppose the wheel bearings are
ok since the horizontal looseness test passed. I would
jack the front of the car up, while an assistant applies
light pressure to the brake pedal you can turn the tire
by hand and look for uneven resistances as the tire
turns. This is what I would do, I'm not suggesting it
is the proper method. You can also remove the rotors
and have them turned, which is what you might end
up doing if you find warped rotors. Good luck.