The Verdict: Need More Info
This route is for the 1991 to 1995 displacement, but a departure before 8 October 1991 points to a lighter one: article 11. Take our Citizenship by Descent quiz.
Article 11 of the Croatian Citizenship Act lets an emigrant and their descendants naturalise without residence, a language test or giving up their citizenship, with no limit on generations. An emigrant left today's Croatia before 8 October 1991 to live abroad permanently, holding Croatian republican citizenship or zavičajnost there.
The main exclusions are departure under an international treaty, renunciation, and moving to another Yugoslav republic first.
If anyone in the line was a Croatian citizen when their children were born, those children may already be citizens by descent, and the problem is paperwork rather than law.