So I had to completely uninstall then reinstall my game, and I couldnt find the ini file to save my scenario completions, so Im currently running all the scenarios to get all my in game items unlocked again.
This is a screen of the second scenario with bare bones, only what the game had in it on installation.
Zoo rating is 87, because the only buildings in the zoo are the ones that were available when I started the scenario, before any research was done, so there are no animal houses at all.
Animal happiness is 98, all exhibits are 10x15 tiles (or thereabouts, I think one is 10x14 and one is 10x16).
Guest happiness is 94, without animal houses.
Hope these screens are helping you figure out how the game works :)