<p>To the OP:
ED - you apply early, if you are accepted by the school, then it is binding and you must withdraw all other apps. (Thus you can only apply to 1 ED school). You decide you will attend around 12/15.
SCEA - you apply early, but you can only apply early to 1 school. (There are certain loopholes to allow you to apply early to other schools such as public schools; please see specific rules for school of interest on website). If you’re accepted the school, it’s non-binding, you have until 4/1 to make your decision if you will attend
EA - you apply early, you can apply to as many schools as you want to. If you’re accepted the school, it’s non-binding, you have until 4/1 to make your decision if you will attend
RD - you apply regular deadline which is later. If you’re accepted the school, it’s non-binding, you have until 4/1 to make your decision if you will attend.
Rolling admission - Turn in your app early or late, whenever! If you’re accepted the school, it’s non-binding, you have until 4/1 to make your decision if you will attend</p>
<p>Thus combos that you may see are ED at 1 school with EA at many schools. Or SCEA a 1 school alone. Or ED at 1 school alone.</p>