Well, I attempted to modify my above post, but apparently an "error" occured. SO:
What I was going to say in addition was that you raise a very vaild point, MB, in that Angelique never really had the chance to harm Julia until 1840, which by our timeline was late in her career, but by her timeline was still very early. But, I still think there was some sort of divine intervention, apart from the writers (because they clearly missed some dramatic gold!), because even though Angelique was under Nicholas' control for a while there, she didn't seem like the type to follow orders if it didn't suit her needs. I mean, it seems to me, anyway, like she disobeyed Diabolis a number of times, but when Nikolas was around, she followed him. So does that mean that Nicholas was more powerful than Diabolis, perhaps the Devil Incarnate?