|1908 Sears Roebuck Home Kit Sold for $1548|
Your unauthorized reproduction of designs and schematics may trigger an angry response from the developer but here are three strategies that could deflate any incoming lawsuits:
The documents are not protectable under copyright law. Not all building designs are protected as architectural works under copyright law, only original buildings designs created after December 1, 1990 that show permanent “humanly habitable structures." In other words non-original building designs (designs copied from another source) as well as walkways, landscaping and similar outdoors components are not protected. Also elements of the design that are functionally required - for example windows, door and other staple building components are not protected.
You are permitted to use the designs as a fair use. Your limited use of the design for a transformative noncommercial purpose seems to be a classic example of fair use (Here's where you can review the fair use caselaw). However, you may need a legal defense fund because the final decision about fair use is made by a court.
The developer is seeking to silence opposition in violation of a SLAPP law. If you believe someone is suing to silence you from participating in a public discussion about the new development, check to see whether your state has a SLAPP law (short for strategic lawsuits against public participation). Claiming a violation of the SLAPP law may enable you to have the case dismissed and have your attorneys fees paid as well. Note: SLAPP laws are not a defense to copyright infringement per se; they are a claim that the copyright lawsuit is really being brought to silence opposition. To succeed you must demonstrate that free speech is at issue and that you are likely to prevail on your copyright claim.