@Veqryn:
can you move a submarine into (not through) and stop in an enemy controlled sea zone during combat move, and choose not attack?
No, you can’t. However, in AA50 and AA42 if there are no enemy destroyers you can submerge at the beginning of the first combat round, effectively avoiding combat.
@Veqryn:
can you move a submarine into (not through) and stop in an enemy controlled sea zone during Non-combat move?
In Revised, no. In AA50 and AA42, yes, regardless of the presence of enemy destroyers.