Genesis 6:4 states there were giants (Nephilim). The Book of Enoch, Jubilees, and a few others help reinforce this and pick up the story where the Bible left off. Long story short, the fallen angels and giants create religion to worship themselves as gods and Lucifer is the first and greatest of the angel/human giants. About 10% survived the flood thus they are mentioned in the Bible a few more times (Goliath, Rephiam).

Satan is the adversary, or the accuser, as the book of Job mentions him. The central figure of evil that runs the whole show. Lucifer is a fallen cherub as you pointed out, and "son of the morning". Lucifer is believed to be the Anti-Christ which points out the mimicry as Jesus states that only he himself is the true morning star.

If you learn about all the ancient religions they all central around the same characters just different names and stories for them. So in this set up it is just a continuation of worshiping the false gods and their fake religion. Occults are highly based on Luciferian worship (Free Masons).

If you are into astronomy the Bible says that God's plan is written in the stars and the stars are actually beings/angels. Every ancient religion and mystic sect was balls deep into astronomy. You can learn about how the constellations have been changed and modified over time since they "don't" hold religious value any longer.

I know I tried to pack a lot into a little but hopefully that helped give a little picture. I have been digging around in this stuff for the past few years and it is fascinating. I honestly think I started with where you are as well.