You can readily identify an e-Passport, because it has a unique international symbol on the cover. Electronic System for Travel Authorization (ESTA) ESTA is an automated system that determines the eligibility of visitors to travel to the United States under the Visa Waiver Program (VWP). Authorization via ESTA does not determine whether a traveler is admissible to the United States.
Two to three weeks before the flight date, the price quotes start increasing. This is the time when business travelers start booking. While price drops are still possible, a chance of a price increase is much higher if you wait to book within this time period.
As for the return, the price is about the same no matter which day you return. Currently the cheapest fares for your dates are starting at around $1320 per person and flights for this route can go as low as under $1000, so I would aim for as close to that price as possible when searching for flights.