I have to acknowledge I prefer the gorillas being real gorillas that were changed via extraterrestrial origin, I do wonder about population numbers. Was it originally 19th century? How widespread was the effect? Because if it was just one troop, then the population would still be way to small for a city.
Do we have any idea how canonically big the city is?
Gorillas, of course, do not form pairs/mates IRL - I mean, males aren't monogamous. I know they did in silver age comics, as Grodd was hot for Solovar's wife, if I recall correctly. Did we ever see more polygamous relationships later?
Also, do we know how long the gorillas of Gorilla City live?
Do we know anything about their education system, what age children leave home, etc.?
What about agriculture or foods eaten?