The new park is due to open Monday week (22nd)- no doubt to coincide with the School Hols. The website is very simple- as if saying 'don't expect too much'- at least initially- and the £6.50 Entrance fee reflects that.
Re. the Okapi- If they leave the Zoo altogether it would be the first time, I think. since they first acquired them in the early 1960's- unlike the Gorillas, another of their flagship species, which were absent for just a year or so before Gorilla Island was built. But overall, yes the Okapi would be better suited to the larger area at Hollywood Estate.
On the other hand, I saw mention in one set of plans of their previous paddock(the one attatched to the old Elephant house)being replaced with Bongo though that may not mean much anymore, and again they seem more suitable for the new park. I agree a much smaller ungulate species, e.g. a Gazelle, would probably be more to scale in the Zoo's smaller area.