Have you run the Net Price Calculators for your reach schools? What would your costs look like at these, compared to UIUC and your other in-state publics?
If full-need-met private U’s are as affordable as, or more affordable than, public in-state, then you should consider adding some less-reachy full-need-met private schools to your list. For your interests and stats, Denison University in Ohio is one that comes to mind. (Very strong in poli sci and related fields, with an excellent DC internship program.) Running the NPC for Denison will give you an idea whether aid will be favorable at other, similar institutions.
If you can let us know how the NPC results look for these schools, it will help to refine additional advice.