Well I assume you've looked over the info in my spreadsheet in the first post, given the changes you've made here, I think you seem to have a grasp on how these changes in general are made.
Though I haven't looked much deeper than what we've seen here. I was able to work around a stupid problem that was barring me from properly editing that swap icon image a while ago, but that was my last big accomplishment, and one that others don't have to worry about anymore if they use any of the new themes as a base. I haven't really looked much deeper than that.
@Fangal_Airbag on page 9 located where the switch user files are including some font colors, not sure if they said where they were located or not, though I imagine they aren't too hard to find.
Beyond that, I'm not really sure what more there is to know, we could maybe find the file that has the theming for the screen that pops up when you hit the home button, or we could change the theming of the settings menu, but I'd be lying if I said I had much interest at this time to really look into that stuff. I kinda prefer that the theme isn't active in these places as it kinda sends the message that you should just hurry up and get out of there and get back to actually playing the games lol. Maybe down the line I'll look at it.