I emailed him a few days ago. He said he hoped he'd know in "a week or two" but could not promise anything. But I was asking about Israel specifically. Unsure about any other timelines.
He was very prompt and understanding though. I don't know how much IIE really knows or can do to expedite things.
Tell them that you refuse to give your answer until every fulbright applicant is notified! Solidarity!!!! ... No, sorry, I have no useful answer to your question. But given that alternates are told they may be notified at any point up through the summer, I assume that there is some leeway in making up your mind.