Is Yale your top choice?
No
If you want to go to Harvard first and foremost, REA will “likely” give you two cracks at the apple - with a deferral.
A low percentage get in. A low percentage get rejected. It’s probable (but not assured) you are deferred but could be either accepted or rejected.
Even if you got deferred, you still shouldn’t ED2 anywhere - because if Harvard is your #1 and Yale your #2 - neither has a binding comittment.
You will be somewhere four years, day after day - this isn’t a game. You will get into many fine schools.
But this is life.
Let’s say you ED to WUSTL - and get in.
OK - but now you’re not even giving yourself a chance at the others. So what’s the point of that?