Re: point 1, what is a startup if not a company you are starting...
I generally subscribe to PG's definition of a startup, which is a company designed to grow fast: http://www.paulgraham.com/growth.html
I prefer Steve Blank's, an organization in search of a repeatable and scalable business model. See https://steveblank.com/2010/01/25/whats-a-startup-first-prin... for more.
The two definitions are equivalent though.
1. Any YC advice does not apply to all companies, but only to startups.
2. YC has funded companies in many places.
3. YC is not in SF.
4. This announcement doesn't say anything about location.