I am not sure, I have never heard that you can cross muscovies with other ducks, always was told they don't. I am actually planning on breeding back to Cauyga if I can, so would preferably use one.
How bad are Muscovies at flying off? I have never kept any, but seem to remember (from when I was younger) that they often tend to roost in trees (they are called Flying ducks in German btw...) I am already struggling with my current ducks escaping to the neighbour's pristine lawn ...