I thought I'd post a few updates/notes on your Frankfurt review. Hopefully you don't mind.
1) I saw both the fossa and rusty-spotted cats (

), despite their outdoor areas now being closed off.
2) The Grzimek House remains open and will continue to be, I assume, throughout construction. I don't like nocturnal houses from a welfare perspective, but it really is a stonking exhibit.
3) The diurnal exhibits you list as "Empty" are now home to emperor tamarin / tamandua (unseen) and pygmy marmoset respectively.
4) I assume you meant drills share the exhibit with gorillas and colobus. Neither monkey species was visible today, but the aviary housed turacos.
5) Have you made it to Leipzig yet? That's still the most impressive ape house I've seen, although I'm not sure either Pongoland or Borgoriwald get the formula quite right. Personally, I think Edinburgh's combination of multiple day-rooms and non-naturalistic visitor areas is the winning approach.
6) The walk-through aviaries are temporarily closed.
7) Yep, just addax now. For a large paddock, I agree it's under-utilized, but they do look good in there.
8) I know what you mean about euphoric zoo visits. Nothing else like 'em.
Also, I forgot to mention in my previous post that Hannover has a new exhibit for drill and De Brazza monkeys opening this summer. Enjoy!