1) Yes https://asiamedals.info/forums/rising-sun-orders-made-by-hirata-workshop.627/
2) Circa 1890s/1910s. Definitely not an early Hirata-made 2nd class (not to mention that early 2nd class didn`t have a neck badge) https://asiamedals.info/threads/early-meiji-era-2nd-class-rising-sun-order-breast-stars-in-hexagon-cases.23183/
3) Original pin was removed (you could still see the traces of fitting) and screw was added. Silver screw plate was taken from Imperial Russian badge (if it original and not a replica).
4) These are Russian marks (most likely from 1908-1917 time period).
5) Yes, 42. Typical technical mark of case manufacturer that could be found inside Japanese order cases.
Best,
Nick