[Facts] Write as in Cyrillic?
You need to go to View, Encoding and choose Cyrillic (Windows) to read those
Ivo - Èâî
Ivonildo/Yvonildo - Èâîíèëäî
Ivanildo - Èâàíèëäî
As I said, I have never heard of Ivonildo or Ivanildo, and I am guessing they are newly coined versions of Ivo or Ivan.
Ivan is the Slavic counterpart of John.
Ivo is considered to be a nickname for Ivan, Ivaylo or other names that start with Iv-, or it may be derived from iva - the colloquial name for a type of willow.