While there are those here that have a problem with the use of the names "ninja" and "samurai" and the images they invoke, I take no issue with them. Though clearly Japanese in flavor, the image they conjure is still fantasy, despite a cultural jump from West to East. With the number of Western-specific cultural names (Bard, Druid, Paladin), this is acceptable. I do take [mild] issue with the name "Gunslinger," however.
Not only are we given gunslingers, but they also have grit. This is a very "Wild West" archetype, a genre era on the wrong side of the Age of Enlightenment. The alchemist borders on technological, but remains firmly rooted in the Renaissance and the Gothic. I wonder if a more fantasy-appropriate name for the gunslinger would be Musketeer.
Like the Alchemist, the Musketeer is just on the "correct" side of the Age of Enlightenment. Like the Samurai, it refers to something very specific historically, but fairly generic culturally.