Ok, to get to AA basement you need to get gloves from LairBear.

After gloves, you climb up in barb fields to talk to Trapper....that activates Archaeologist in BDC to accept the set of 4 different Spectre statues, which then lets ya use the castle stairs down to Consort / AA.

set folks up with set of 4 statues, usually easiest if you kill the NE spectre last -- and beware that the stairs hex is a super heal hex for that Spectre.