Nice choices. But I personally would do a primate pack, with apes amd monkeys. And, I'd add into the game hybridization. For example, Bengal tigers aren't full Bengal, but are hybrids with Malayan tigers (at least a while ago). I'd make it where you have the challenge to find a full blood animal like that, and there's a risk of getting a hybrid instead. So, that's why I have certain choices in my list. Here goes:
Asia:
1. Sumatran Orangutan
2. Northern White-Cheeked Gibbon
3. Proboscis Monkey
4. Hamadryas Baboon
5. Sunda Slow Loris
6. Silvery Lutung
7. Rhesus Macaque
8. Siamang
9. Golden Snub-Nosed Monkey
10. Tapanuli Orangutan
Africa & Madagascar:
1. Eastern Lowland Gorilla
2. Mountain Gorilla
3. Coquerel's Sifaka
4. Aye-Aye
5. Cross River Gorilla
6. Olive Baboon
7. Gelada Baboon
8. Indri
9. Drill
10. Golden Monkey
South America:
1. Common Marmoset
2. Golden Lion Tamarin
3. Brown Woolly Monkey
4. Black Capuchin
5. Golden-Faced Saki
6. Guianan Squirrel Monkey
7. Mantled Howler
8. Black-Headed Spider Monkey
9. Red-Faced Spider Monkey
10. Bald Uakari