Thanks, I have Priority Pass access via Chase SR, but I've had middling luck with it domestically. I might try the UA lounge; 3 of us are arriving on paid UA J fares, I'm 1k, and at a last resort I still have two free passes, so maybe something can be worked out. Question: Is the UA/*A lounge available after we pass through immigration?
As for visiting Seattle, we'll be there before the Japan trip, and 6 hours is kind of short when you factor in immigration, etc. In reality we'll probably have 4 hours at most to kill in the airport between getting off the one flight and preparing to board the other.