Hi Ivan,
The b&w's are much more powerful for this subject. They depict the people in a stark, cold atmosphere that photographically replicates what the subject people actually experience.
Regarding how you greet and interact with those you want to shoot . . . Milton Rogovin, now deceased, became a nationally known photographer whose images of poverty are now in the Library of Congress. He lived and worked here in Buffalo, NY, and I had a passing acquaintance with him and his wife. He did the same thing with his subjects that you suggest. Show them the images, give them prints and treat them gently, but as ordinary people. Do not look down on them or give them any reason to believe that you do. Rogovin did 2 ten year projects shooting 3-4 dozen people each time, then going back ten years later to shoot the same folks, then again another ten years later. He shot the parents and their kids, their kids' weddings and their kids; their tiny shabby homes, with broken windows, their torn and wrinkled clothes and the streets where they spent their time. He told the story of poverty with his camera far better than the written word could ever do. His images were . . . are memorable.
From that series, he produced a book that he updated each time he shot another series. He gave copies to his subjects. They knew him, greeted him when he walked down the street, welcomed him into their homes, etc., etc.
So from watching him work, I know it can be done successfully and gracefully. But it is a unique skill; that is the ability to relate easily with folks who have so little, so much less than you. Rogovin never offered his subjects money to pose for him. He was, instead, their friend. I have high admiration for Rogovin and for anyone else who can relate so intimately with a group of people who have so little and must live so difficult a life.
Congrats to you for taking on such a series, and good luck to you.
Zen