Can you play an offensives card and not declare any battle hexes? I am at a point in the game where the Jp are so reduced that consolidating their position makes more sense than attacking and using the Log. value plus HQ eff. would allow many more activations than just using the OC of the card plus HQ eff.
In a related question, can you split your activations between strategic and normal movements? I think the answer to both questions is yes but I can't find the answer to either question in the rulebook except by omission - the rules don't specifically say you can't.
You don't have to declare battle hexes. Attacking is voluntary. Note however that if any of your units end their move in a hex with an enemy unit you MUST declare that hex a battle hex.
Activations allow you to move your units in any way you want as long as the moves are legal, there's no problem in splitting between normal and strategic. The only restriction I would say is that if you activate a stack of units, all of them must move in the same way. If you need to have some units within a stack move with regular offensive movement and others with strategic unit, just activate them separately in the same offensive.
Enemy ground, air or HQ unit forces the moving ground unit to stop and declare a battle hex.
8.11 An enemy naval unit does not require a battle hex if a friendly ground unit just moves through it. (I assume the hex would be captured, and the naval unit would need to emergency move away, correct?)
Also, looks like voluntarily stopping at a hex which has only enemy naval units would still create a battle hex.