this is my theory on who J. Douglas reeli is. picture this:
as we know after this past episode, she is "SLOTH" of the 7 deadly sins (how many do we have now? lust, greed, sloth, gluttony, envy...5. we're missing pride and wrath). she has ties with the military now - however, because of maes' deductions, we're not quite sure if Sloth really is Juliet Douglas or if she's just taking the form of a deceased Juliet Douglas (much like Envy was doing with Basque Gran).
and we all know that the Sinners are Homulculous (sp?) - not quite human. but think. what if Sloth really is Trisha Elrich? Al noticed her before, mentioning to Ed how much she looked like Mom. And you have to admit, she unnessecarily does. during the transmutation of their mother, ed and al were kinda preoccupied being absorbed by the void. when al woke up, ed said that he killed the thing that "wasn't their mother", but when the camera panned over it, it was still moving slightly. plus, how thorough can your killing be when your arm and leg are missing, and your brother is no longer in his body? when they came back to burn the house, there was no mention of trisha's body being there.
It would give the Sinners a reason to go after the Elrich brothers other than the Philospher's Stone. so yeah. i think that sloth is trisha, since we don't know if the remains were actually destroyed.