OP: I wonder if you were only accepted by Stanford if you would be reapplying as a transfer to H,Y, and / or P ?
Your stated reason for transferring (major offered by Stanford but not at HYP) shows that you did a poor job of selecting target schools when applying for admission as a freshman as a high school student. Or, it could also indicate that you really only chased prestige and were hurt by the rejection from Stanford.
Which other universities offer your desired major ?
If Stanford is the perfect school for you, then why didn’t you apply EA to Stanford initially ?