Five Letter Boy Names

Maori form of Isaac

This is most familiar here as a musical name, via Indian Parsi conductor Zubin Mehta, but it certainly could be used by others.

Same problem as Eóin -- squared.

Greek name featured in the New Testament.

Neele's roots can do in different directions- In Germany, Neele was traditionally a unisex name derived from Cornelia and Cornelius, but today has gone strongly to the girl's side (similar to Evelyn or Ashley today in the US). Neele is also an English surname, such as the British judge Richard Neele and poet Henry Neele.

Biblical name from the Old Testament.

Kauno was derived from the Finnish word kaunis, meaning "beautiful."

Merce Cunningham (born with the French version Mercier) was a highly influential avant garde dancer-choreographer and his name still resonates with an aura of bold originality.  

Obscure and quirky, but not without some appeal.