In general, where EA is possible (i.e. not restricted by REA rules), it is best to apply EA because many colleges with EA become more selective (or their popular majors become more selective) in RD because EA fills up most of the space.
So I would amend the above to say:
- If applying ED1, apply EA to all other desired colleges where it is offered, other than where REA prohibits applying REA there while applying ED1 anywhere.
- If applying REA, apply EA to all other desired colleges where it is offered and which are not under the REA college’s restriction against applying EA, or where the other college has REA that prohibits applying REA to your REA college. Some REA colleges only restrict against applying ED elsewhere, but others restrict against applying EA to other private schools in the US, so read the REA rules carefully.
- If not applying ED1 or REA, apply EA to all desired colleges where it is offered.
If any college has rolling admission, apply as early as possible for the same reason that EA should be chosen where possible.