This is the answer but be warned it is a major spoiler so if you dont really want to know move on.

highlight the area from start to end to see the answer on how to get more then 50 elders.

Start

The Island event involves a mirror and choosing the right word, but which word is different every time cause which one gets the right answer is random. the right word clones the villager, so hense if its an elder, you will have a second elder.

End