I originally put something up about BU on the results page, since lots of people are asking about notifications from them, but noticed that my post was removed, so I'll put it here instead as a PSA.
Based on fb Draft group posts/my own intel, I can tell you with 100% certainty that they made their initial fiction offers during the last week of March, and a top 30 was also selected at that point. I haven't heard about anyone being waitlisted, so it's possible that only candidates 1-10 were contacted, while 11-30 are still in the dark about where they stand but it's also quite possible, especially this late in the game, that they've notified everyone in the top 30. I was told that they had over 500 applicants total this year, and around 350 for fiction. Applications went way up this year, presumably because it's the first year they're offering full funding.
Oh! Edited to add that I haven't seen anything in the fb group about anyone turning down Iowa.