+C. W. Marshall
As is noted in the original post, the graphic is very much work in progress, little more than a rough sketch and typos are part of any work at this stage.
The purpose of the graphic is to provide a quick and easy map to the politics of the gods in the game. It does not reflect where they live or their parentage.
In the context of the game, Olympians are those gods which both nominally support Zeus and which the player characters can have as patrons. Both Hades and Hecate fall into this category are thus included in that part of the graphic. Other figures such as Persephone fall into different categories and thus shown in a different part of the graphic.
I appreciate you are trying to help and the your feedback is useful but please remember this is a rough draft of a graphic which is summarising 60,000 words of setting text.