Question about ED I, II and EA

I wanted to apply to 4 schools EA, and Northwestern ED. I saw that Vanderbilt had ED II. Am I allowed to apply to NW and Vandy ED? Or do I need to apply to Vandy ED I to be eligible for ED II? Similarly, am I allowed to only apply to one ED program, so will I have to choose one of the schools to apply ED?
Thanks in advance!

You can apply to only one school EDI and so you must choose. You can apply to multiple schools EA unless they are restrictive EA (or single choice EA). If you are accepted to your EDI school you are in a binding agreement to attend and must withdraw all other applications including EA applications if they are still pending. If you are rejected from your EDI school you are free to apply EDII to a different school under the same terms (as the earlier EDI scenario).

You can’t apply to one school EDI and another school EDII unless you are rejected from your ED I school (if you are deferred from your EDI, you could also choose to apply to a school EDII).
You can apply to as many EAs as you like as long as they aren’t Restrictive EA (like Yale, or Stanford, or Harvard).