I have never had a problem getting into the Alaska lounge with my PC membership and I am always on a Co flight to IAH. The original poster with PP might have a problem as they dont have the same access rights from the begin.

Also of note, there is a Delta lounge that is bigger and has about the same offerings. I did try to go there to get a Mojito but of course the bartender there didnt have knowledge on how to make one.