Short answers, pulled from the story.
The production budget of Seven Samurai increased from 150,000 dollars to 580,000 dollars because the project ran out of money in 1953 and required an additional sum from the studio Toho. The final budget swelled to between 556,000 and 580,000 dollars as the production stretched over 148 working days to complete the film.
The co-screenwriters of Seven Samurai were Shinobu Hashimoto and Hideo Oguni, who developed the script over six weeks of intense collaboration with director Akira Kurosawa. They created detailed family trees for the village residents and instructed actors to live together as if they were real families during the shoot.
Akira Kurosawa filmed the climactic battle in Seven Samurai using a multi-camera setup and telephoto lenses to create a sense of momentum and compress the space. The scene took about two months to film, during which the cast and crew risked frostbite in the cold temperature and artificial rain.
Fumio Hayasaka composed the musical score for Seven Samurai and recorded the music in the spring of 1954 over the course of two weeks using magnetic tape recording. Hayasaka wrote 300 orchestral sketches and decided not to use music in the film's final battle sequence to heighten the scene's sense of realism.
Seven Samurai was released in Japan on the 26th of April 1954 with a runtime of 207 minutes, making it the longest Japanese film released at the time. The full-length roadshow version was later cut to 160 minutes for general release, and the film was recut multiple times for international distribution.