I haven't heard any news about Hajime Isayama creating another manga. Usually, such announcements would come through official channels or reliable sources, and there haven't been any of those yet.
I think it depends on his inspiration and motivation. If he has a story he's passionate about, there's a chance. But it could also be that he wants to take a break or focus on other things for now.
I don't know for sure. It depends on a lot of factors, like his inspiration and personal plans. We'll just have to wait and see if he makes an official statement.
As of now, I haven't heard anything regarding the making of another 'Christmas Story'. It could be a possibility if the producers see enough demand or have a great new idea for it. However, remakes or sequels often depend on various factors like funding, availability of the original cast (if they want to bring them back), and market trends.
There's no indication that they are making another 'Christmas Story'. Usually, for a new movie in a series or a remake to happen, there are pre - production rumors or announcements from the studio or filmmakers. In this case, there's been complete silence, so it's likely not in the works at the moment. However, the film industry can be full of surprises, and a sudden announcement could come out of nowhere.