I don't see any new species coming in. The zoo just doesn't have the capacity for much more. I don't see any phase outs either - but I don't have much behind the scenes knowledge. Unfortunately my member emails don't give out to much information, and their social media tends to lack in certain updates (ie births and transfers) unless it is a spotlight animal. I can only gleam so much from my notes!
The zoo does take part in some SSPs (Takin, markhor, gibbon, red panda), but it has a lot of senior citizens and animals that are just being held, like the amur tigers.
The open range exhibits are relatively plain square enclosures with rotating animals on the main road in the zoo. There is no theme, and seems to be used for separating sexes. There is one with rockscape where I've seen the serrow and the markhor. Not a great picture of the exhibit, but they don't hide much.
As for the wolves, I am sure they are grieving. They are a pack of siblings. As much I hate to say it, Slate and Bear are not much farther behind. I doubt they will leave the wolf exhibit empty for long though - it was upgraded not too long ago and its a beautiful exhibit. I am not sure it will stay wolves, but we will only see with time. I could see them switching out for arctic wolves, but I'm not sure if many other species will fit that habitat. It is very open.