So for your characters who do like to prepare, what are their rituals? (They're bound to have some). What happens to them when anything interrupts/stops their usual preparations and rites? How do they handle that? For those characters for whom the thought of planning is anathema, are there occasions in the story when they really wished their attitude was different? What went wrong for them to make them wish that? (Good possibilities for both comedy and tragedy here I think).
A lot of fun can be had setting characters against each other (as long as it genuinely serves the point of the story) and a wonderful clash could be between a planner and a pantser. They simply are not going to see the other's viewpoint. Again good possibilities for comedy here.