elizabeth - what a well written piece. you covered bases that aren't often figured into that equation. unfortunately the "homeless" we become aware of are usually the problem people. and that's why we , in general, equate  homeless to be problematic. and the mentally ill get pushed through and aside all the time. if it can't be seen - it doesn't exist. 
 i befriended a woman at  the park i take my dogs to - we have a great time visiting. it was a couple months before she told me she was living in her truck.. how her, several other women and a few sympathetic guys park together for safety to sleep at night. where she goes to clean up.. resourceful woman for sure. i admire her, have offered help that she refused. the only help she'll accept is  sharing a lunch i bring to the park. i can't even speak of her as homeless - she bristles.
 this is not an easy thing. i do think st vinnies should be at any meeting regarding affordable housing and involved in it's inception. they have it down.