Yeah, the code they use for HD/Aerie is very much like the code they use for the four PC romances, but obviously keys off HD talking to Aerie instead of HD talking to the PC. So HAERDALISROMANCEACTIVE refers to the state of things between HD and Aerie, LOVETALK under HD refers to the progress on the track between HD and Aerie, etc.
If it's at 13, that means you should have seen "You have come to me, my goddess! I have prayed for my love not to be denied, and my majestic queen appears before me!" which is a couple of talks past the "mouse" one.
I really don't know what might be holding things up, but I have a guess. This is the point where, if there is an active Aerie/PC romance, the actual "triangle" business starts up. You do have the romance going with Aerie, so it looks like something is waiting. You might try setting HAERDALISROMANCE to 1 to try to force him to get to the next talk, or using the AdvanceRealTime(99999) trick that some favor now.
(I'm all but certain it's not us causing the problem, though.)