Even in coach, your chances of finding three award seats on relatively short notice during a holiday season are quite low. Apart from the timing and the number of passengers, however, award seats with a connection of a few hours in Europe (not a stopover; that's something different and would be more expensive) should be possible to find if you can be flexible with your schedule. On another note: BA imposes hefty surcharges on long-distance award travel, even if you use AA miles to book. Try to find flights on AA itself and/or its other partners to eliminate or minimize such added fees.