I do not think that it is going to happen
By the time you come off of the waitlist at 3, you will have already committed to Ivy 1 (if the commitment date is still June 1). Remember they probably won’t call the waitlist until they know the yield.
Ivy 1 will have no reason to go back and look at your financial aid again because you have already committed.
Should you come off of the wait list at Ivy 3 and if you feel the aid is better at 3, then go to 3 if you are chasing the bag.