Dear student,
I would consider adding private DC schools that may potentially give you merit money as well as great political exposure, namely Georgetown, GW, and AU. With the same aim in mind, I would also add smaller private schools known to be connected to the political world - i.e. a few more 7 sister schools, not just Wellesley. I would consider writing your essay about babysitting your siblings, and how that shaped your character, both from the stand point of loving your baby siblings, as a community service, and as sacrifice. Someone, somewhere, is going to dig it.
I would consider taking out UVA, UNC-Chapel Hill, and Berkeley unless you have specific merit opportunities in mind. State schools do not readily give scholarships to OOS students. Academically, UW-Madison is at least as strong as all of them, including in your specific area of interest.
Also, just because you are not low-income in Wisconsin, you may well be low-income for those top schools. I would expect that your financial aid package in those schools would be significant.
Good luck!