I keep going back and forth on what the PZ-related content of the stream might be. And I do feel like we need to be prepared for it to not be quite
as big or as much time as folks may be thinking. The stream happens on (a) the day the new console DLC drops, and (b) the same week that console gets a physical copy of the game.
So they'll definitely be devoting time to that. And then there's the PZ PC news... I have no clue.

If the trailer and/or free update info drops in advance? It could just be a re-hash of that. They might reveal something
during the stream (which seems unlikely to me). Or they may just say "Hey, we told you ones coming and there is - we promise - just give us a bit more time!" Or some odd combination of any of those. Haha. Could go a lot of different ways.
Point being: A few of those 'options' could be covered very quickly. So between that news plus the console stuff they've got going on this week? The hype would make sense, and they'll still be devoting a bit of time to PZ across platforms, even if the PC portion is relatively brief. And mind you, the PC portion of the livestream can be pretty short and we'll
still get the best news ever! Hah.

It took them like, 10 seconds to assuage people's stress about the Barnyard pack and let us know that the pack we're now anticipating would be coming!
It's also very funny that this post could be fully irrelevant within like, the next 8 hours. LOL
This thought crossed my mind as well. I'm with you in that I'm not thinking there's another pack coming but... I'm hoping that whatever details we get about the next DLC lead us to (B) thinking it's the end (e.g., bigger than usual, Zookeeper collection), or (B) thinking there's one more because it would pair with another pack (e.g., Old World pack theme) and they outright tell us that it's one of two.
Not on the hype train for that yet, but the logic logics and I'd be totally down. Haha.
I definitely think it's possible that there's a Latin American species or two in the mix! Maybe more. As much as the dictionary is a decent source of information, and I do believe that it's a reasonable source for speculation, there's no guarantee that it's complete (some animals may not have been added to the dictionary yet) or that all of them will wind up in the DLC ultimately (maybe secretary bird and dik-dik are in but none of the other species are; just an example).
Lots of different ways it can go and I
really would find it strange for them to fully ignore Latin America... Especially considering the hype around the coati.