Almost. The first recorded use of ‘Zero’ was in Mesopotamia in 3BC/BCE. https://www.history.com/news/who-invented-the-zero

Nope. 1 BC/BCE -> 1 AD/CE. That’s just how it was designed.

It’s 2 years of FEATURE updates, usually longer for security.

I’d say keep it basic with Ubuntu. It’s not exciting, but it ‘just works’ out of the box and there’s TONs of support if you can’t figure something out.