IIRC, it went from 25, briefly to 30, to 35, to 50 by the end of the war... But finding a reference for that is proving quite difficult, though I am prone to going down ratholes when it comes to learning about the details of WWII.
I don't know about that. It seems like smaller airplanes get tossed around too much to accurately depict how a bigger airplane flies.
Per that link, there are six airworthy. However, they're pretty optimistic about calling something airworthy:
1) 44-8543, owned by Erickson Aircraft Collection, wearing "Ye Olde Pub" markings and registered as N3701G, is legitimately airworthy and currently touring Canada.
2) 44-83514, owned by CAF, "Sentimental Journey" registered N9323Z, is legitimately airworthy and also currently touring Canada.
3) 44-83546, owned by Military Aircraft Restoration Corp, wearing "Memphis Belle" markings, registered N3703G, is "undergoing heavy maintenance" and last flew in 2021.
4) 44-85470, owned by EAA, "Aluminum Overcast", N5017N, also grounded since 2021.
5) 44-85784, owned by Imperial War Museum Duxford, "Sally B", G-BEDF, is airworthy and flies in the UK, seemingly mostly just from Duxford.
6) 44-85829, owned by an unknown owner since being sold in June, N3193G, last flew in October 2023.
So, there are just three that are actively flying, and a fourth of unknown status at this point. Hopefully the other two will eventually return and the seven additional ones that are supposedly being restored to airworthiness can one day return to the sky. However, those have been under restoration since 1995, 2005, 2008, 2011, 2014, 2015, and 2021. It is clearly not a fast nor easy process to get these birds aloft again.