Potential illegal renovation found before closing

We had an architect in to discuss a bathroom renovation we want to do after closing. However, this architect pointed out that the current configuration is likely the result of an earlier illegal renovation -- which even if the board approved in some form, the DOB would not have in its final form. The issue is that an interior room which can only be called the living room does not have sufficient... [more]

We had an architect in to discuss a bathroom renovation we want to do after closing. However, this architect pointed out that the current configuration is likely the result of an earlier illegal renovation -- which even if the board approved in some form, the DOB would not have in its final form. The issue is that an interior room which can only be called the living room does not have sufficient access to windows. He counseled us that applying for our legal renovations might cause us to need to remedy the illegal setup as well, which would mean removing a bunch of walls that we happen to like. Is this something I can bring someone in to verify on our final walkthrough and then perhaps renegotiate based on (day of closing)? If true, it definitely violates the terms of the contract, which state the seller made no illegal changes. If so, what sort of official would I bring in to determine this? Any advice on how to renegotiate? We'd probably consider purchasing anyway if reasonable terms could be reached. Thanks much :) [less]