I think it will happen. They choose the hardest to place first. After all the sloth bear it does feel a bit out of place in the Eurasian DLC, being the only tropical/warm westher species there so it's inclusion (even if i love it) feels a bit forced. Why not the Palla's cat or the markhor instead? Those whould've fit perfectly with the overall theme and feels of the DLC. Yet the chose the sloth bear.
To.me that means that the next two packs will give us the spectacled bear (Mountains, LAM, Arboreal) and the ABB (Boreal, Arboreal, Woodlands/Forests).
That's my small personal theory based on nothing