The Hawaii bowl is almost always Christmas Eve.
The Diamond Head Classic is Dec 22-25.
The MW is rotating out of the Hawaii Bowl once and the Vegas Bowl once in the next 5 years, but they haven't said when yet or who will replace the MW is those two bowls.
The Hawaii Bowl was filled in as a guess for 2015 here before the Diamond Head announcement.
http://www.loyalcougars.com/future-football-schedules/
Thanks, ESPN.