Has anyone performed a housing survey or market feasibility study? I think it's helpful to go back to basic supply/demand economics to begin searching for answers (relative to the mix of low income/market rate housing). Often, we tend to focus on the "free money" (tax incentives/credits or, in some cases, grants) first, and that frequently results in an outcome that is not market-driven; the market must then adapt to the strategy instead of the other way around. Not much good results from that.
Asked another way: what is the demand for low-income housing in your market area? And what is the demand for market rate housing? Too much low income housing will chase out prosperity, in my view, when what is really needed in depressed areas is to attract wealth and prosperity. I am making the assumption you want your community to meet the needs of people at all socio-economic levels. Determining the ideal mix--that's difficult. Markets tend to do that for themselves through supply and demand, but when government incentives are present that can skew the answers.
To summarize, I would suggest 1) identifying what the ideal outcome looks like--i.e. what are you trying to create? 2) Why-for what purpose? and 3) using research methods to test the market and determine if your vision for the community is shared by community members.
I am no expert--my answers are based on my experience in government, community-building and residential construction/real estate development. I hope this is helpful.