DS Class of 2018 was waitlisted 3 years ago and he was told that the list was no greater than 50-75. He eventually received his TWE in early June but had already accepted USAFA appt. we had heard rumours that very few if any at all were pulled from the list. Best of luck and ensure plan B is solid.
Long time ago, a close family friend's DS, Class of 2007 was waitlisted and he was told that he was #7 0n the wait list. He eventually received his appointment 2 weeks before graduation(May 28). He is successfully commissioned and now LT in the Navy.