Typically, I define the Weird West genre to be movies that take place in the Wild West and include some supernatural element. This usually means some sort of horror element like vampires or zombies, but that isn’t really a requirement. So a movie with cowboys and dinosaurs fits my definition, even though it isn’t really what I picture when I think of Weird West.
Yes, it has legendary Ray Harryhausen’s stop-motion action, but the whole movie just seems silly to me. I don’t know, I guess I’d call this one “Weird West, but I don’t care to watch it”.
Here’s a trailer. I don’t think it’s streaming anywhere right now though.
No, just a subverting of tropes isn’t Weird West to me. As I said, it has to be significant. Something that implies much larger implications to the setting/world. Examples: steampunk tech, some alien/scifi tech, magic users, fantasy creatures, etc.
Even better for me is if it feels like a seamless addition. Like if everything about the town is a standard Wild West town but is also a low magic setting where some heirlooms have enchantments or a magic user is uncommon but not strange.