AI staff in CCU have clear instructions not combine tickets, even single PNRs/tickets are not interlined if its separate carriers. The reason they even entertained/tried your request is because it probably was all AI. The ESTA data is uncommon for Indians, as most pax will have US visas. That said its linked to your passport number, which must have been in the reservation already, so the system sends your passport number over and not other data.

Pilots ar either of the chatty type or not. Not very different from other airlines.