This was definitely my favorite bestiary update yet. The fallen are a classic enemy and I am glad that Blizzard is keeping them the "comedic relief" of the series but still adding to them.
Concerning the two other types of fallen, look at the new concept art
If you look directly to the right of top of the shamans staff there is a fallen with different horns than any of the other ones. It is hard to tell because he is cut off, but I think it might be possible that this is one of the two other types. What do you think?
"The people pray for strength and guidance. They should pray for the mercy of a swift death. For I have seen what the darkness hides."