I made an account to clarify in this thread (and to you): I have read the theater pamphlet with the Gen Urobuchi interview myself, basically everyone you mentioned is just speculating and is mostly incorrect, even the second person who also said they read the pamphlet is choosing to interpret Urobuchi's words in a strange way.
Urobuchi started writing the script in 2014 (one year after Rebellion), but he said he didn't "have any ideas." Inu Curry, specifically Doroinu, then sent Urobuchi his sketchbook/idea book with a plethora of ideas, and Urobuchi decided that he thought it would be interesting to use whatever ideas he wanted from Inu Curry's brain and make a story out of it. He quite literally uses the analogy of going to a Chinese restaurant, seeing what ingredients there are to choose from, and deciding what to cook using those ingredients.
It's not that he was "hired to execute Inu Curry's ideas", he chose to use Inu Curry's ideas as a base for the movie script. Now, Rebellion underwent 3-4 major script revisions before it was completed. The first version was only 70 minutes long, and as we know that film is 110 minutes long (excluding credits). Chief director Shinbo asked Urobuchi to do revisions for Walpurgisnacht (because Urobuchi was focusing on other characters, and Shinbo personally wanted to focus on Madoka). Urobuchi was unable to do those revisions due to scheduling conflicts and gave Shinbo permission for the team to edit/revise/do whatever they wanted with his script
The team thought about completely redoing the script or revising the whole thing, but around 2021 they decided to just use what Urobuchi had written and make some revisions. According to Urobuchi, the entire first half of the film is mostly unchanged (which Urobuchi thinks is for better and for worse, he criticizes himself but also lauds himself at the same time). Inu Curry led the revisions for the second half of the film, but it's not like he rewrote the entire thing or was finishing an unfinished script, he was using the original script and revising it as would have happened during Rebellion or any other standard production (with explicit permission from the chief director).
People lambast Inu Curry for the Magia Record anime, but Shinbo had explicitly told Inu Curry not to adapt the game (which Inu Curry was involved with, as a writer, even), so Inu Curry instead pursued an anime-original route. However, Inu Curry was already involved with the script during the 2011 TV series. Urobuchi didn't come up with the Faust symbolism or witch backstories, that was all Inu Curry's revisions to the scripts and storyboards. They also added a whole scene in Rebellion, and corrected more of the storyboards for that movie than Shinbo himself. Basically, they had always been involved in the writing to some degree, that involvement became more pronounced in the movies, especially here where Doroinu has co-"screenplay assistance" credit for the first time
So, there's definitely a difference between their writing styles that probably had an effect on how this movie turned out, whether or not people think that's good or bad, but I really wish people stopped trying to say Urobuchi didn't work on it. He was hands-off after he had written the script, but he did note that he went to some of the voice recording sessions and even discussed some of the performances/lines with sound director Youta Tsuruoka, and he mentioned that he was very happy that the movie has finally been released.
Sources for every claim I made: Walpurgisnacht Theater Pamphlet (2026), Magia Record Official Guidebook Volume 1 (2021), Rebellion Official Guidebook (2014), and Madoka Magica Official Guidebook (2011).
