That's fantastic that the guitar is as good as you hoped.

Regarding the knob stiffness, it may just be a matter of lifting the control knob up a smidge. The plastic scratch plates aren't perfectly flat, so sometimes if the knob is pushed down too far, it will rub against the scratchplate at certain points.

As longs as everything looks in order, I wouldn't worry about the strings appearing used. It had to have been played at least a little bit! The way I sweat, if I played it for 15 or 30 minutes, the strings would be tarnished.

Hurry up on those dishes so you can get to playing!! :-)