I guess, though I do not know the fish and cannot see the amount of distress she is in, I would recommend using salt to control the parastites while you get the dropsy under control.
Parasites can exasperate any condition, making it worse, but when push comes to shove, the dropsy is an urgent, life threatening condition that needs to be addressed immediately if not sooner. The parasites can wait until a more opportune time.
Salt and Maracyn are compatible. The salt may kill some parasites, will definately slow them down, and will not interact poorly with the Maracyn.....
Dropsy, huh..... man, that is too bad.

I am sending my best wishes to you.....