What are the 3 characteristics of people that live in Hooverville have?

I would say that the general population of the Hooverville that Bud and Bugs enter in chapter 8 is a friendly, kind, helpful, and giving group of people. When Bud first enters the town, he has to ask a group of grown men the name of the place. To the men's credit, they do not brush off Bud or say things like "Get out of here kid!" Instead, the men are friendly toward Bud, they answer his questions, and they smile about it too.

The man smiled and said, "Well, son, any place where there're other folks in need of the same things that you are is the right place to be. This is exactly the Hooverville you're looking for."

This is actually a bit surprising to readers because the man that Bud is talking to is white, and Bud is black. This book is taking place long before the civil rights movement, and racism is a very real and powerful thing that Bud would have to worry about.
Bud's interaction with these men gets better and better because they not only help Bud know where he is, but they also make sure that he gets fed. They are able to tell just by looking at Bud that he hasn't eaten well in a long time, and they make sure that he knows where to get food. That is a generous offer from these men, because they are all equally homeless and hungry.

Someone said, "Brother, why don't we feed these boys? That one looks like he ain't eaten in two or three months". . . . The mouth organ man said, "You’re welcome to join us, but we all pitch in here, so's unless either one of you is carrying one of them smoked West Virginny hams in them bags, it looks like you'll be pulling KP tonight."

I would say that it is important to note that the homeless residents of the Hooverville are not lazy people. They understand the value of work, and their words let Bud know that they expect him to pull his own weight if he wants to be a part of their community.