I do understand when Diana is in Themyscira, Nubia and the rest of the Amazons should show up, but considering that they may spend most of their time on the island, when Diana is in the Man's World the least I expect other than Siggy, Etta and Steve, is that the Wonderfamily is present on a recurring basis. I also think that not using the Holliday Girls with Etta was a miscalculation.
I guess it's Anahi, the Esquecidas' oracle