One thing I've been thinking about lately is, just how, as a director, do you have the other orphans react when the Mudges show up?
With all the scripts floating around - some based on the '99 movie, one I linked to on Youtbue has a bit of '82 to it, very cool foreign one (in Jerusalem) has Punjab singing the countries of the world from Animaniacs (start about 41:40) and space limitations meaning the orphans all heard Miss Hannigan and Rooster plotting and signalling "no" just before the "jig is up" check is read - I"m sure there's multitudes of ways to do it. I wonder how they originally did it on Broadway.
In a way, you'd thnink they'd at least be mildly stunned, like, "Wait - Annie's parents are real?!" Sure, Molly believed they were out there, but at least some of them really mocked the idea. For them to *only* be paying attention to their gifts seems odd...unless Miss Hannigan told them. I could imagine her saying "Mr. Warbucks will have everything taken care of," so then when the Mudges are taken away, the orphans just figure he knew they were phonies.
That got me to thinking of Miss Hannigan's plans. In chapters 5-6 of this story, I developed what I think her plan was - I won't give a lot away, but suffice to say, she figured if the Mudges took Annie, she'd lead the orphans in "Deck the Halls" anyway (they seem quite ready) and then make her getaway to rendezvoul with them while the orphans perform another song or two and have all the staff's eyes on them. (You'll have to see what I envision - earlier in it I also show my idea of how they developed Hard Knock Life" as a skit, what happened when Miss Hannigan left on that Coney Island trip, and other things.)
I think some glancing over makes sense - a little shock, or at least curiosity. But, if they don't have any reaction, they knew something was up. And, if they were really thinking about it, and what would probably be some strange behavior from Miss Hannigan the previous day or two, they might have done some sleuthing before, and maybe even managed to get some information to the Warbucks' via telephone that would give *just* enough of a hint as to where to start tlooking so it isn't the logjam of events happening all at once at the end.