The story is quite interesting so far, and I can see your plots evolve which story you write.
Power corrupts, and Immortal Power is no exception. Living in seclusion does only postpone the issue, while having the potential of making one forget the value of companionship. To have Harry brought by characters of such... potential.
I am though interested to find out how you are going to draft the fact that Slughorn was aware of Horcruxes, and implied that he knew more about them: "Don't ask me to tell you more about this."
I'm anxiously waiting to see where this plot is going and what will happen to Agathon.
Osiris ruled part of pre-dynastic Upper Egypt as a god until he realized how corrupt he had become. He yielded part of his power to balance that (he is using part of the power now, with the Acolyte and Tutmoses' permission). The brothers who don't wish to stagnate are welcoming Harry, their link to the modern world. Those who are afraid of change or are too proud to change, will be against him.