Well I may not be able to gauge just how large the Havana safari exhibit is, I believe that if it can house elephants, buffalo and rhinos, the size should be well large enough to avoid conflicts. D'you mind linking any media for the exhibit (if there is any)?
However, even with this size, I don't think that removes the trampling risk for the cranes. I'd also like to make a note again of the fact that only two Northern White Rhinoceros individuals exist in the world (and I don't mean in captivity, I mean captive and wild) which would make them impossible (quite literally) to acquire in a realistic situation.