Current zoning requirements are contained in Chapter 55 of the Village code (PDF) (available online). If you cannot meet the zoning requirements, you must apply for a variance. Since the Building Department cannot predict whether or not the Board will approve a variance, we cannot determine if a property is able to be built upon. Furthermore, the applicant may be subject to the requirements of other government entities, such as the Suffolk County Health Department or the Department of Environmental Conservation, which may or may not allow you to build on a lot.
The building department does not furnish letters regarding what may or may not be built on a property.