I believe that’s fine. I know BC isn’t exclusive against other EA schools. Not sure about UChicago. I just knew about the Cornell deal particularly because that was the exact same situation I was in 2 years ago when I was getting ready to apply
yes, you can apply EA to BC and to Chicago. But note, EA at BC is pretty competitive, so if you need that GPA boost for senior year grades (with mostly AP’s!), you might wait to RD.