That sounds cool! If you want to change the files yourself go for it! If you or a friend are computer savvy, you can also fork the project to make your own Spanish version. You can also download the .zip file with all the source code and try building it yourself to make changes. There are instructions for running the project at the main gitgud page.
https://gitgud.io/argonvile/monster-mind/-/blob/main/source/poke/buiz/BuizelDial...
Here is the file with all of Buizel's dialog! So you might change "#buiz04#Oh yeah, I'm not sure your answer fits with that <first clue>..."
to something like
"#buiz04#Oh sí, no estoy seguro de que tu respuesta se ajuste a ese <first clue>..."
or whatever. Be forewarned it will take a very, very long time. Even if you are a professional translator doing this as a full-time commitment, I would expect to spend several years on it!