Very nice! As a biologist specialized in systematics (though only very recently!), I've held for a while that paraphyletic groups can still be useful, and this is excellently argued.

About note 13, though: Vegavis, a bird from Latest Cretaceous Antarctica, has been placed by the latest analyses in the modern order Anseriformes, which today includes geese and ducks. That implies that, at the time of the last dinosaurs, birds had already diverged into four clades that would survive the mass extinction: Palaeognathae (today including ostriches, rheas, and other large flightless birds), Anseriformes (waterfowl), Galliformes (land fowl), and Neoaves (all other living birds).