I've got a question regarding motion in NFHS rules (I'm a pretty new official). Any input would be appreciated.

From 7-2-7
Only one A player may be in motion at the snap and then only if such motion is not toward his opponent's goal line.

Sit: WO has established himself as a back and goes in motion angling toward his opponents goal (and his LOS) but is running somewhat parallel to the LOS.

Is it only illegal motion if he is still angling toward the LOS at the snap?

Prior to the snap, if the motion does not simulate the snap, is a back that goes in motion toward the opponents goal legal?

(In 7-2-7 it seems as if the player in motion can be going any direction as long as he's not specifically going toward the opponent goal on the snap)

He cannot be going towards his opponents goal line "at all" at the snap. Both of your examples would be a live ball foul for illegal motion at the snap.

Not possible. He's either going toward the goal line or he's moving parallel to the LOS. It's an either or sitch. He can't do both at the same time.

Agreed. What I was trying to indicate (and apparently not very well) was that he is running off angle, like maybe 3 degrees off parallel.

Can the player go in motion any direction legally as long as they are not going toward the opponents goal at the moment of the snap?

Yes. The motion man can move backward, forward, sideways--whichever direction he wants before the snap. However, he must not be moving toward his opponent's goal line at the snap.