It's hard to say for sure. Sometimes the cast's schedule and availability determine if they'll attend Comic Con. Keep an eye on the entertainment news for updates.
I don't have that information. But you could follow the social media accounts of The Flash or Comic Con for any possible announcements regarding the cast's presence.
They are one and the same. Whether it's written as Comic-Con or Comic Con, it represents the same gathering of comic enthusiasts and the showcase of all things comic-related.
No, Comic Con International doesn't own Comic Con. Different organizations or entities might be involved in organizing and managing various Comic Con events.