I had a friend who's parents used to have emus. They get big, like look you right in the eye from the same height big. It takes strong secure fencing to keep them. Not sure how they are around other birds either. I know we weren't allowed to go in the pen with them.
On the flip side, I'll totally be following how this goes for you. I love the idea of having emus, but wasn't really open to taking the plunge without seeing how they worked for someone else. Very much hoping this goes well for you!