Aren't the sizes ranged between small and medium? IIRC, that's the size range of all PC races now. So, IOW, it's up to you to decide how big your individual character is, pretty much the way it has been all the way along. How is this different?
Look, I'll be the first to admit, I haven't really paid any attention to Strixhaven. It's just not my thing, so, for these specific issues, I really don't know. But, I look at what's happened to the drow - massive expansion of lore, the orcs - massive expansion of lore and think, hrm, yeah, we're seeing pretty big explosions of lore based on bringing more nuanced versions of race to the table.
AFAIK, only the Owlin are officially added to the game right? The rabbit person appears in a UA article and not meant as the final product. To be fair - I just took a peek at the Owlin writeup and I totally agree - that's seriously lacking. Wow, that's just a complete non-race. I have to admit that I hope that we'll see more expansion later on down the road.