Large cast cash coins - and four inches is large, for a cast cash coin - are almost always charms, intended for mounting inside or outside of a house. to bring good fortune.
In this case, the inscription on the coin is the same as that found on coins of the Guang Xu emperor (reigned 1875-1908). While there are some large cash coins from the time period of this emperor, they don't have two dragons on the other side.
You'd have to ask an oriental weapons expert about the sword; China does have double-edged swords, known as "jian".
Wikipedia. But if it "came with" the medallions, then it too is most likely a "Feng Shui replica". The emperor's era-name, "Guang xu", literally means "light beginning", or "enlightenment".
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis