1) Not neccesarily. There might be a small correlation, however, you cant predict if a person will have breast Cancer only due to their bone mineral density because the probability for a woman to have breast cancer is pretty low (below 5%). According to the data given, women with high bone density are just 3 times more likely to have breast cancer, thus, the probability will be just 15%. There might be a correlation but you need more information than just the mineral bone density to predict breast cancer, there might be other causes that are not related with mineral bone density.
2) It is impractical to conduct such an experiment. The problem lies in the fact that you cant fix the amount of mineral bone density a woman have. 2 women with different BMD might be quite different in different aspects one from the other, so you wont be completly sure that the cancer was caused in one case just because of the mineral bone density alone. An ideal experiment will have identical bodies differing on mineral bone density alone, but that is in practice impossible to do.
