Let me just chime in to add that while there are many, many elements that are not tiki in and of themselves, they can and do fit comfortably within a tiki context. The Creature from the Black Lagoon is a great example. It is not tiki. You may deck out your bar space with every bit of ephemera related to the Creature and make it look like an underwater lagoon found somewhere deep in the Amazon. This will not make it tiki. But you can add the ol' GIll-Man to an existing tiki space and he fits right in. I have one. Many other tikiphiles incorporate Gill successfully as well. More broadly, nautical decor--ship's wheels, rigging, wooden grates, portholes--isn't tiki either, but almost every great tiki space I've been in (including the hallowed Mai Kai) incorporates nautical extensively.
When you said "Captain's Jacket" I immediately thought WWII ship's captain in the Pacific theater. Lots of folks incorporate WWII themes into their tiki space--James Michener's Tales from the South Pacific is a foundational text of the early tiki movement, after all. But after reading the comments I'm thinking your "Captain's Jacket" is more along the lines of yacht rock, which is a relatively new (and ironic) addition to the tiki scene that isn't universally accepted.