Regarding your son's connection in SEA to a late night flight to PDX, rather than overnighting, if he is standing in front of an agent, and there is an award seat on one of the late planes, and he turns on the charm, his chances should be pretty good. One of you should check the load on the 6am plane, and if it is full, try the argument that if Alaska puts him into a seat that would otherwise be empty on the late night flight, then can then sell his seat on the morning plane and it becomes a win-win. The attempt at this line of reasoning, whether it is true or not, often generates a chuckle on the part of the AS agent and may be just enough to get him on his plane of choice.