Most of the Jews of Northern Macedonia left before the War, and most of those who remained were murdered. In terms of genealogy, ask in The Sephardic Diaspora group on Facebook, of which I am an admin. Maybe also the Central Archives for the History of the Jewish People, in Jerusalem, and some of the aid organisations. If any of the Jewish families had foreign citizenship or protection (a hangover from the Ottoman period) you can check with the archives of those countries. I am especially thinking of Spain which was neutral, although not many Sephardim had Spanish nationality. Have you checked with eastern Sephardic synagogues, especially in Israel and Seattle? Might there be information in Italian and Bulgarian archives?
Best wishes,
David Mendoza
President, Sephardic Genealogical Society