I have been doing a lot of research on colleges but some websites are not very clear. My question is, Can I apply to MIT, Caltech, UIUC, and University of Wisconsin-Madison for early action?
You must visit each of the school’s websites and carefully read the criteria for each regarding their EA program. When I did that 3 years ago for my kids, both MIT and Cal Tech allowed you to apply EA to more than one program. I recall UChicago and Tulane being the same. However, things change year to year, so reviewing what is posted on the websites NOW is important. If you have doubts after doing that, then ask your GC for their interpretation. Alternatively, copy the language that is unclear and post it back here for a review by others.