The Zoning Board of Appeals shall not grant any appeal or request for a variance or issue any special permit without first holding a public hearing. Notice of such hearing and of the substance of the application shall be given by publication in the official newspaper of the Village at least 10 days before the date of such hearing and within 45 days after the filing of such appeal or application and by posting the property with at least two signs 8 1/2 inches by 11 inches in size. In addition to such published notice, the Zoning Board of Appeals shall cause notice to be given of the substance of every appeal or request for a variance and of every application for a special permit, together with notice of the hearing thereon, by requiring notices thereof to be mailed by the applicant, by certified mail with return receipt requested, at least 10 days before the date of said hearing to the owners of all property abutting that held by the applicant and all other owners within 200 feet, or such additional distances as the Zoning Board of Appeals may deem advisable, from the exterior boundaries of the land involved in such appeal or application, as the names of said owners appear on the last completed assessment roll of the Village. Provided that due notice shall have been published and that there shall have been substantial compliance with the remaining provisions of this subsection, the failure to give notice in exact conformity herewith shall not be deemed to invalidate any action taken by the Zoning Board of Appeals in connection with the grant of an appeal, variance or to issuance of a special permit pursuant hereto.