These are just small problems that need solutions.

Good work calling the mayor and tracking down the possible solutions to move forward.

Take each hurdle as it comes and then find the solution and go to the next one. 

There are numerous possible solutions, but they depend on many factors, especially what the goals and objectives are for each individual partner/member. 

I personally like to stand behind what I sell and would work on a solution. 

Making lemonade out of lemons is probably one of the best adages I can think of for learning to be creative and solving problems in real estateif there is a problem with a property or dimension issues you dont always have to go to a contractor to solve the problemcontractors have a certain mindsetand are operating on a specific paradaigmhere are some solutions I have done in the past that have really worked and paid dividendsi had an ejector pump in a bathroom and the space was covered by a makeshift door I decided to have a custom cabinet built that functioned as a trash receptacle and had shelves as well now the unsightly space is home to a beautiful custom cabinet that can be easily removed for servicing the pump when it needs it problem two I bought a house that had front of the shower enclosure removedrather than buy another shower enclosure cost 500.ooi opted to replace the front wall with backer board and tile the front and ended up with a beautiful custom look cost was cheaper than replacing shower enclosure and the look is twice as good problem threewhen i bought my house there was a hole knocked out one of the walls about the size of a  door i suppose thieves came in from the crawl space into this part of the house when it was vacantrather than close in the spacei enlarged the crawls space door poured a concrete floor and created a second exterior doorway to the space making the downstairs ready to become a legal apartment. 

I think if you are in a higher price point and you have a more upgraded cabinet/kitchen you can get away without it if that is the clean modern style you are going for.  

Or any other solution to this problem.

Is the only solution in those cases to dig up the slab? 

The trouble is that the owner has a partner who may or may not agree and would just want cash upfront. what would be the best solution for this problem?