We need some help understanding what options we have with a kitchen in a house we own (i.e. need to make some budget friendly changes without tearing it all down and rebuilding).Who should we talk to?

The part that you're missing is to build/rebuild your reserves and improve your credit.

If so I would do like others said and just rebuild it from the plate up. 

It is usually one day for demo and 1-2 days to rebuild.

The only way to go 1 to 2 really is a knockdown and re-build as a 2, that has the best chance in my opinion, but still hard if there are no other multis in the area.

If it is the unpermitted issue, then you have to determine if the permits can be issued retroactively and if so how much risk you have that you will need to rebuild some portion of the structure.

We're almost complete with the rebuild but the insurance adjusters are only paying about 75% of the actual costs to conduct the reconstruction of the property.  

He thinks it will be tens of thousands of dollars to fix, and said I should probably just get a GC to quote a tear down / rebuild instead of having him do an inspection. 

@Justin Martin you would really need someone who is not just experienced but has experience in dealing with your local building inspectors and permiting office to see what is expected from them.Based on the potential things you have listed, that would be almost like a complete rebuild (sometimes more), so unless you are buying the property for the price of the land, I would be careful.

Could you be responsible for rebuilding it.