I know they have their detractors cos thet aren't really in captivity, but as someone who doesn't particularly mind that: marine iguanas! Just such great potential for some cool looking habitats!I'd say that the tegu is the best bet for a reptile. For 1, we got the big 3 tortoises typically seen in several zoos, crocs would feel like a waste (unless it was African, but them again this DLC seems to be centered around the Americas), and monitors fall under the same boat as crocs (the perentie is the only one I'm personally interested in)
I highly doubt we'll get a 3rd caiman, especially after receiving the spectacled caiman