Thanks for listening and commenting. I see that the way I phrased my usage of scale makes it sound like I'm using a C Lydian but I'm not. I think when it comes to Japanese music theory it can be pretty confusing, and for me a bit hard to understand. This is mainly due to how Western theory often can't really explain Japanese music. From a Western perspective, you can call (almost) all of the Japanese scales penta scales and call it a day. This however, while right from one perspective, doesn't really explain the hows and whys of the Japanese music.
Here I used the C D E G A in the melody but C is not the fundamental tone (the tonal center), I should have written it as A C D E G. F# and B are never in the melody but in the chords. The melody itself has a fundamental tone and depending on what tone is the fundamental a certain chord is played by the sho. In all of these chords F# and B are present, I even used one with a G# if you can spot it :P
Scales =/= modes. Yes, I have the same notes as C Lydian but the harmonic context, the fundamental tone, and maybe most importantly, how it sounds is different to C Lydian.
There are many kinds of different "Japanese music" and they can behave differently and follow different rules and it can be a bit of a rabbit hole. I'm not following all the rules myself and there are many things that I am uncertain about and might have misinterpreted something. Here I choose a scale and applied the chords based on the melody.
Sorry for long comment and again thanks for listening!