As far as I know, for Colorado, you have to be a resident of Colorado to apply to the early acceptance program. I do not know much about applying to Colorado's program but for Purdue, you accept the offer to enroll in their university as an undergraduate student (which means you have to reject offers from other colleges) and then apply to the early acceptance program. So it means you are going to purdue regardless of getting into their early acceptance program (one reason why I did not apply). For Missouri, you apply as an undergraduate student and after you get accepted (it's rolling admission, I believe, so you can receive acceptance letter early), you apply to the early acceptance program. However, you get acceptance letter for the early acceptance program around the end of April so by the time you need to pay enrollment fee to a college you've committed to, you will already know if you are accepted or not to the early acceptance program. (most of the colleges require you to accept/reject their offer in the beginning of May)
Hope this helps!