Back in May, Alaska Lounges stopped allowing guests for Priority Pass members, mainly due to overcrowding. Now they are allowing guests again and have updated their conditions to allow two guests per cardholder as of August 7th 2017.
This new rule applies to all Alaska Lounges, except the Anchorage lounge.
It still states that access may be restricted due to space constraints, and that has happened in the past.
HT: DoC