Who's missing?
Who isn't missing? There's one vampire court. One clan of ghouls. One wildfae embassy, since it happens to be in Chicago anyway. The two fairy courts. The wizards. Marcone, as host, and four other freeholding lords: Vadderung, Ferrovax, the Archive, and the Naga from the Ghoul-Goblin comic.
Who are missing: the other 5 remaining vampire courts; every other ghoul clan in the world; the rest of the wildfae (like Erlking and the Tylwyth Teg); the Venatori Umbrorum; the other sixteen freeholding lords. (We're told in White Night that there are about twenty total, pre-Marcone.)
Who else is missing: Anyone or anything from any continent other than North America. Even the White Council of Wizards sent its three North American Senior Council members and its four North American Wardens (plus Christos and Chandler). Vadderung's an exception, being European, but since Marcone is sort-of his protege, it makes sense that he'd show.
My theory: This isn't really a pan-Accords meeting. It's Marcone's party, and he got everyone with an interest in Chicago to show up, except the Tylwyth Teg (who were dealing with a sudden leadership vacuum). Drakul has no interest what goes on way across the ocean. Ditto the Ukrainian shapeshifting guru. And the Jade Court. And the Kenku. And the Miksani. And the Leyshiye. And the Rakshasa. And the Loa. And the wacky Lemur-folk of Madagascar. And so on and so on...
One weird line in the book -- when Harry makes Carlos's warden cape flap around as a distraction, we're told: "Several dozen security teams bolted for their primaries..." This is odd, since we've only been told of fifteen or so "primaries" if we're counting Etri and Evanna as two, Mab and Molly as two, and all four Senior Councilors as individuals.
So... perhaps there are twenty or thirty other delegations around, and we just weren't told about it?