edub, have you ever been to Mexico?
In my 5+ years in Mexico, I have only seen three homeless people on the streets. I will admit that I've never spent much time out in the streets at night in a big city here, but it sure ain't Detroit or any other US city in that aspect... retirement security here is in the form of owning your own house, in the form you can afford and maybe having several kids who end up living nearby to help you in your later years instead of relying on an expanded government welfare/retirement net.
Most days here, there are a few little old indigenous ladies from outlying pueblos sitting in doorways, wrapped up in seven dresses and a serape with a hand out in El Centro, but they NEVER say anything other than "gracias" or give people a hard look of expectation. They sometimes have a small grandchild or two with them. They do appreciate any pesos placed into their hands, and they go to their homes at night.
I've never seen kids here put to work selling anything in the streets, but I know it's different in places like Tijuana where weekends bring in Americanos with dollars in their pockets coming down for the beaches or to party. (that used to be me).
Many Mexicans may not be well educated, but these days they generally have more manners and respect than many university graduates from "rich" countries.
Maybe you can check out the ****** gulches at Playa del Carmen, and target the tourist bars/businesses in Cozumel and Cancun with your business. Then you'll just have to step over passed out drunk tourists instead of any annoying homeless people.