As planned, Subaru checked the AVCS next. They found one was advancing the timing 8 degrees and one was advancing 3 degrees. It stands to reason they should at least be the same (and probably shouldnt advance at idle???). Given they are different, they are optimistic that this is what throwing the misfire code. They couldnt get it back together by the end of business Friday, but I should know more Monday.
I should also note that only one cylinder, #4, is repeatedly firing the mis code. #1 was in there the very first time, but has not been replicated since they starting diagnosing the problem.