In response to your idea's
3) several mods do this already but I don't see a good reason to limit player choice like that. I intend to add the emperors children, world eaters, and thousand sons mods so adding marks of chaos would be redundant.
4) I have no idea how to do that if its even possible.
5) don't start changing tons of things on a whim. Choose one task at a time, let me know you're going to do it, and only change files related to that task. When you're done upload only the files you made/changed to your google drive, then I'll download and test them in the current build.