Congratulations!
Radio Maria, when they opened were at the top of their game with a nouvelle mexican cuisin in a fun room in the historic downtown Champaign area, what else would you expect from a restaurant owned by architects. Sadly, over the years, the quality has slipped and we have stopped going.
I would recommend the brunch at Silvercreek in Urbana on Race street just south on University. They food is very good and the atmosphere is nice enough that you won't feel out of place in wedding attire, but by no means stuffy. They usually served good quality brunch standards, some of their warm stew items (beef burgundy), cold smoked salmon, etc.
http://www.couriersilvercreek.com/silvercreek/
As for your second request, Silvercreek is owned by the same people as The Courier Cafe - this is where I would go for breakfast, since the Elite Diner closed a few years ago. Good food, made to order, for breakfast and lunch.
On your other choices - I have been to Biaggi's - it's basically a Maggiano's knock-off - there is one near the Barrington 30 movie theater on Barrington Road just north of I-90 if you want to take it for a test run.
http://www.couriersilvercreek.com/silvercreek/