the 1st and 2nd were taken from operas: Carmen Abigail and Tristan Nibelung.
the 3rd needed a name that was workable in the USA, the UK, and Russia, and that's a tall order, but thankfully there's Nicholas - Nick - which works in all those places. His grandmother, who doesn't speak a word of English, calls him what sounds like "Knee-Key".
Nicholas is a masculine form of Nike, the goddess of victory. His middle name, Gabriel, was the product of a lengthy and sometimes heated debate. I favored Sterling, but DDGW absolutely wouldn't hear of it. No way.
Tristan, meaning sad, was apt because he was born in Germany on their national day of sadness. The German authorities - who must approve the names of children (for obvious reasons) - were reluctant to allow his middle name, Nibelung (for obvious reasons). But they finally relented based upon my being an American and paid up member of several Wagner Societies (they actually wanted to see the receipts for membership), had I been German, they would have forbidden it.
Had Nick been a girl, I would have chosen Wyatt Neva.