I wonder, can we count them as Legendaries? The UBs are kind of strange, since there are multiple ones of certain species. (Though Sun and Moon had a bad habit of making multiples of several other ones too...)
I mean, they do have a full event for them and are a major part of the plot. If there was more time spent in their world where they're common, then maybe they couldn't be considered.
I suppose so. I'd consider them fringe Legends. They're almost full on ones, but are debatable. Technically speaking, (Spoiler Alert) the cover Pokemon might be UBs in a way, so that makes it debatable.