Extraordinary Ability Visa

Absolutely not. This is why the O-1 is the 'Golden Ticket'. It circumvents the brutal 65,000 H-1B lottery limit entirely. There is no numerical cap on O-1 visas, and they can be applied for at any point during the fiscal year.

Theoretically, yes. After the initial 3-year grant, the O-1 can be extended in 1-year increments indefinitely, as long as your U.S. agent/employer can violently prove that the original 'event' or a related follow-up project is still actively ongoing.

No. Dependents (spouses and minor children) are issued O-3 visas. O-3 visa holders may study in the U.S. but are completely, legally barred from engaging in any employment whatsoever.