You don't have to look as far as ants to make the analogy you are making. Almost no animal, and even some plants cannot reproduce without some minimal number of "tribe" members. This is true for anything from chimps to probiotics.

This all depends on how you define "life" and "individuality": slippery concepts. And it's hard to not confuse those with emergent behavior once you do get millions/billions of individuals together. Sure you could treat NYC as its own autonomous living organism. Or you could treat it as millions of individuals. It certainly doesn't make sense to treat it as gazillions of cells.

The idea of having free will has been debated for centuries, but intuitively I think it's obvious that a human has more free will than an ant.