There are likely not any solutions that will make everyone happy in this case. This means that we have to find a solution that will be least bad. This will, however, depend on which stakeholder's point of view we are looking at this from.
I think that the initiative that the businessowners suggested might have been a good way to go about taking care of the problem. If the affordable housing advocates had lost the initiative, they likely still would have been angry, but it would have been much harder for them to claim that they were being oppressed by a big corporation since it would have been a vote of the people that defeated them.
Another possibility (though we are not given enough information to know if this would work) would have been for Disney to have helped the affordable housing people (and perhaps Sun Cal) to find another site that would have been suitable. That way, the resort district could have been protected (which is very important for Anaheim's economy) and some more housing could have been created for low-income people.