What you have to keep in mind is there are a lot of different influences in play. There are the names, which Matt based on his family like his father Homer, mother Margaret, sisters maggie and lisa and also the street names in Portland such as lovejoy, kearney, flanders, etc. Then there are the looks and occupations and general characterizations which were based on other people. By the time the voice actors got to them they were already defined, but then they may have based their voice and mannerisms on someone else, so there are lots of answers for each character not just one, so everybody is right!