Kathey pacific recently started 777 till Hongkong, (previously they had the Dragon Air's smaller 767 aircraft) but The issue is timing. They start 2 am from Zia, fly towards east and reach hongkong airport at 5.45 am. Virtually you can't sleep during this short flight and the connecting flight departs in 5 hours. The Hongkong- Toronto flight is the 4th longest flight in the world. :-X. Way too much. I think night traveling without proper halt is an issue for families with kids. Kathey pacific is known for it's good service though. Turkish would be just fine comparing cost versus service and transit is at Istanbul with just about an hour. You reach fastest by Turkish. Interestingly for prices you can explore PIA, as you can avail business class with only 1,54,000 taka return and it's the cheapest with one year open, they had a promotional fare, please check if it's still valid. You get 3 star hotel at Karachi any you fly in style. Problem would be the airport seal of Pakistan in your passport. Your might face problem visiting USA ;D. Otherwise it was superb according to few of my elderly relatives. The best is Emirates I guarantee, still the most expensive.
Wishing very best.
