When I look at Kata I think of kung fu forms. One movement may have different applications and no one says "there is zero evidence that the application was intended from that movement" when someone stumbles or discovers another application for that movement. Then it's either going to work or not work. If the application works then the technique is valid and that move can represent that application. I believe this is how the martial art technique evolves.
In Jow Ga I can show one movement and give you multiple applications from that one movement. I will use a sweep for example, In Jow Ga the sweep is always taught to students as a low sweep. Similar to this
For me my sweep has a wider application range because I'm a deceptive fighter. When my Sifu first saw me do my version of the back sweep, he keep telling me that I need to get lower like the guy in the picture. He stopped telling me this when he saw that not only can I do the sweep without being this low, but that I had better mobility with the sweep when I wasn't this low. You know what he didn't tell me. He didn't say "There's is zero evidence that that the sweep was intended to be done from that position." The way that I do my sweep gives me 2 additional applications adds 2 deceptive appearances that aren't in the original sweep that is taught in all the Jow Ga schools. Based on what you stated, While there is no evidence that the way I do my sweeps were ever used. There is also no evidence that it wasn't used that way.