For the vast majority of models and airfoils, 1/3 of the way back from the leading edge of the wing, is the rule of thumb that will get you safely up and back down again. Rarely would the CG be further forward. A more rearward CG results in a more responsive airplane, to a point, but too far to the rear and the model will become uncontrollable.

As for your stabilizer. The misalignment you mention is probably not serious enough to worry about. It means the airplane's trim in the yaw and roll axis will change as you move the elevator, but probably not enough to really cause a problem.

Trainer type models are frequently out of trim, misaligned and not the most well balanced. But a good instructor can put it into pretty good flying trim for you, and you will learn alot about flying and about airframes by fussing a bit with it.

Have fun