I think there's a distinction to be made for having a target and overcommitting to "a" target. The targets present themselves as the flow of movement unfolds. In a sense, I would guess that we ought have multiple targets at the same time, and it's a matter of finding our way to one or more of them, through the manipulation of other targets (targets we're not trying to cut so much as get to move out of our way).
Yes. Well put.
At the moment of cutting, it is necessary to have a specific target to cut effectively. Exactly what that target is cannot be predetermined, however, but must evolve from the flow of the encounter.
How much time between identifying the target and actually cutting it? That depends on the skill of the swordsman.