Ball joints looked good upon inspection too.
I just took the car for a quick ride to pick up rock salt and there is absolutely zero pull one way or the other when on or off throttle.
As for the feeling it in the floor, the shaft runs and attaches right there. If it is binding it should be felt right there.
As for locking the steering wheel, I don't think my wheel locks. I even just went out to verify and I turned it lock to lock with no key in the ignition and it never locked.
What you described about your issue sounds like a slop issue, which would definitely point to the rack. I have no slop, just a thunk. When we had it jacked up we wiggled the wheels to look for play and there was none.