RE: Engine Offset
Right.
The torque produced by the engine will tend to pull the plane to the left, especially when taking off or when quickly hitting full throttle during slow flight.
The engine is offset to the left so that you can add right thrust and still have the prop shaft in the center of the cowl. Right thrust will help to counteract the left torque generated by the engine.
Many planes, trainers in particular, will also have down thrust to counteract the high lift generated by the flat bottom airfoil of the wing.
These explanations are an oversimplification, but they'll give you the right idea.
Welcome to RCU!
Dennis-
(edited for spelling.)