During the disaster, we found that all of us can handle many jobs needed at that time regardless of our formal position. But once the threat is past and search and rescue is complete and the area is stabilized, then many move back into their traditional roles.
However, as you point out the focus could have changed somewhat. This is when the council needs to possibly be meeting with citizens and businesses to determine if maintaining existing planning documents is the direction to take or is the devastation so extensive that a whole new plan should take shape. I believe some cities have elected to rebuild in a whole new direction while others - such as London after the great fire - chose to maintain the existing design of neighborhoods/roads/etc.
As for the potential loss of personnel, this is also something built into NIMS in that a disaster might go on for some time so there is a chain of succession established and this planning acknowledges that not everyone might be able to function in their normal capacity.
What I wonder about is the obvious loss of revenue that the city will experience. If homes and businesses are gone this will affect the revenue significantly so I would imagine that's something the finance and admin people are trying to identify and plan for. But there are probably case studies of these types of challenges also out there for review.
It's interesting you mention human capital, because I don't think we do enough planning for that even when we aren't faced with disasters. And I believe that is a significant asset of a community that we don't pay enough attention to.