If you go to Edinburgh Zoo again, Gilly, look out for the volunteer guides (turquoise sweatshirts or T-shirts) They are stationed near the enclosures to talk to visitors about the animals and are very knowledgable. A lot of them are retired teachers or nurses, so they know how to interest children and explain things to them. Then there are the ten-minute talks by one of the education staff at a dozen places a day, which are usually accompanied by an extra treat for the nearest animals - this brings out the ones who were kipping behind the bushes out of sight. It is particularly good if Barry the fabulous communicator is on duty that day (pony-tail, built like a night-club bouncer, which he used to be before he took this job).
The reason there are no elephants is because they need to live as a family or they are unhappy, and there just isn't enough level ground for a large enough group. There used to be giraffes, I don't know why there are none at the moment. One reason may be the slopes - if a giraffe trips and falls and breaks a leg it is pretty much a goner. They are difficult to anaesthetise safely (blood pressure problems with the long neck)
There ARE lions, Asiatic ones, up near the tigers. One of the drawbacks of the hill, as well as the thin soil over the volcanic rock, is that by the time visitors have puffed halfway up they run out of enthusiasm for going further. The answer is to start by working your way up one side of the area without deviating sideways too much, and seeing the animals at the top first. You can then zigzag downhill to see the rest.
I agree with you about the cafe. It is a franchise, nothing to do with the zoo itself. They make plenty of profit from expensive events in the big house and I have a feeling that they see the cafe visitors as a captive source of money.