I have no idea if this actually happened I do know that Disney would absolutely announce an opening date with absolutely zero intention of actually hitting it. Everything you saw/heard last weekend was a knee jerk response to Anika Noni Rose's 2024 claim. All of it. They had no prior plans of making any Splash Mountain announcements this past weekend.
So, I would consider the late 2024 date to be basically nonsense. That being said, expect the attraction to close after the winter holidays. If they are actually serious about it, it would be closing at the end of August and we'd have a closing date.