Sugar river is beautiful mostly sand bottom. I'd consider it a yak/canoe river - I've never waded it and never would. Kishwaukee is really multiple rivers with the various branches, it varies a lot depending where you are. May be all sand/silt bottom, other sections all gravel. Definitely sections to wade your best bet is study all the public forest preserve areas on google maps in Boone, Mchenry, Dekalb, and Winnebago counties and go explore (when waters are normal or low). Pecatonica is not wadeable. Its deep sandy and silt. Apple river is great wading, beautiful but access is very limited aside from state park and public hunting land. Rock river when low is certainly wadeable in short sections. Other considerations are Illinois river tribs (creeks and rivers like the Vermillion which is certainly wadeable and beautiful - just be careful it can run quick and best at low levels).
You may want to consider sections of the Dupe, Fox, Kank, and Des Plaines that you haven't waded before. You may be surprised what you may find. They are rather long rivers but if you study google hard and are willing to walk some distance to get access at a park or bridge (or ride a bicycle) you can hit some areas that have less pressure.