That is my take. I looked at the Eagle seniority list and it looks like around 28% are already AA pilots and the bottom 47% were hired after AA stop hiring. That leaves about 25% that would be hit with one list. I would think that would be an easy fix with a fence. A big part of that 25% are making over 120K and have less than 5 years to go so they probably wouldn't want to go to AA anyway.
As far as bringing AA pilots at Eagle to AA prior to furloughs, I wouldn't be surprised to see AA start recalling next year to mitigate any disruptions.
If APA can see that they could put together one list without losing any seniority whereby gaining all RJ flying back, I see that as a no brainer. I believe that if you give the Eagle pilots pay for TOS and have a fence to prevent furlough fodder then you could get an agreement without much fuss. The hard part is getting AMR on board.