The F&H code is certainly pretty messy so i can see why you are having some difficulties.
As for your last question, Reign of New Gods is made by Platypus_Gems, not me, so you might have to get in contact with them for permission.
As for me i don't mind, just don't claim them as your own, and maybe credit me in some way, either by name(Toby Yasha) or linking to this itch.io page.
That's all!