You often mention that (untrained) humans and primates shouldn't interact, but I was wondering what counts as interacting?
A zoo here in Belgium called Pairi Daiza has a setup where they have two islands, one with ringtailed lemurs and one with squirrel monkeys. The thing is that the visitors are free to come and go and the only enclosure for the animals is the island itself, so the tourists and animals are a lot closer than if they were in cages, with primates wandering onto paths and stuff like that. That said, visitors aren't allowed to touch, feed or throw things at the primates, so aside from the physical proximity there isn't supposed to be any interaction, and iirc there are keepers around to keep an eye on things.
Does that sound like it'd be bad? I'm admittedly a bit concerned now.
When I say contact I mean touching, petting, feeding the animals. If a squirrel monkey jumps on your head in an open-space enclosure, that's A-okay just no touchy!
I haven't been able to find any photos of the islands you describe. From what I understand from your description, it sounds fine! Many zoos have areas where people can walk through lemur, squirrel monkey, and other small monkey habitats.
Like this "lemur loop" at the Marwell Zoo
Or the squirrel monkey enclosure at the London Zoo
The key here is that the humans and animals are simply occupying the same space- as long as there's no human initiated contact I think it's totally fine and normal!
Reminder many animals, including and not limited to primates, can catch and DIE of COVID. If you go to a zoo during this pandemic please wear a mask for the safety of yourself and the animals