Nothing in the bootcamp is really set in stone. What I did with the hellos is I made *any* hello I initiated count. Anytime I said hello regardless of the response, I was putting effort into improving myself.
Another thing I did which I saw in another bootcamp was I didn't include people who work with the public (cashiers, salespeople, etc). Basically, these people's jobs include interacting and greeting strangers. You pretty much expect them to respond rather than the typical stranger.
There's two things that the first week helps you overcome: shyness when it comes to approaching strangers and rejection. Some grumpy bytch didn't say hello. So what? Everytime I didn't get a response, I laughed. It's just funny when people are so unconfident and unfriendly to bother responding to you.