Close. In point 3) it's DOWN trim you'd need to balance the stabilizer's twisted in negative declage in order to cancel out the climb that the twist would try to induce.

Moving the elevator does two things. It alters the usually symetrical stabilizer airfoil into a cambered airfoil and it alters the center line of the overall stabilizer airfoil. The center line being from the leading edge to the trailing edge. So moving the elevator does these two things all at the same time. On the side with the twist it would be passing through the air in such a way that it would appear to be a cambered airfoil that is "flying" inverted. And that isn't going to do any wonders for the drag it's generating either. And as Dick says this higher trim drag will try to push the tail to the right/nose to the left and require some right rudder to counter it.

But again, given the amount you're showing in that first picture the effect would be quite minimal. By all means fix it but if you run into any major stumbling blocks in doing so and can only remove some of the twist then I wouldn't lose any sleep over it. Other factors play bigger parts in the requirement for trimming. For example if an aileron wasn't aligned well with the wing on one side so that there was a step in the airfoil shape it would likely have more effect than the stabilizer twist you have shown here.