I would take I-80 around the south side of Chicago (rather than 90, 94 or 294) and then I-39 north to reconnect with I-90. Fewer tolls that way (though you did say you have an EZ Pass - you might google for the site for Illinois' I-Pass and see if your pass will cover the tolls around Chicago; if so, your only dispute with 294 would be the traffic). Just FYI, I-90 in some sections, especially across Minnesota, can be quite rough (frost heaves between the concrete sections), and that can slow you down.
Sounds like a great trip! Hope it goes really well for you.