I have been thoroughly enjoying this thread, and I very much hope that the zoo that you are describing, Nicholas, can indeed get off the ground.
I wanted to return to the idea of educating visitors through a guided tour, which, in my opinion, misunderstands the reason why people visit zoos in the first place. By definition, anyone on this site is genuinely interested in natural history, and, as such, will be receptive to learning about what they are seeing - even if, like many, they feel constrained by doing so in a group, or they may struggle with the "one size fits all" approach that such a tour would inevitably offer.
However, if I were to go to, say, an art museum, the thought of a tour would be a real deterrent. I don't want to be told stuff. I am very happy to remain largely ignorant. At risk of sounding like a real charlatan, I don't really want to learn a great deal. Instead, I want to potter round at my own pace, see some things, react to them in my own way, spend some time with my family or friends with the nice backdrop of some works of art, and that is it. I think most people have the same attitude towards zoos - that is, that they are for something different, something other than learning (in a straightforward way) about the animals on display.
I don't think this is a bad thing at all. In fact, I think it is good that, for every visitor, there is a different motivation. But I do think it means that, for a conventional-looking zoo, a tour-only approach is not desireable (I think that for a smaller, more niche establish, such as that being offered by
@Batto, things are rather different.
Incidentally, this is also my objection to the Hannover approach to building a zoo. The design of Hannover seems to encourage one particular response, one particular narrative, for visitors, with the possibility that not everyone will want to see this in
this way, to respond in
that way, being ignored.