Looks like those lizards are Holaspis guentheri
, they apparently go by a billion different common names, so you'll be better off searching for the latin name. From what little info I can gather
, it looks like they need AT LEAST 18 inches of height, and preferably bigger than that.
You might have enough space for a mantis, provided you added a lot of perches since it's a glass tank.
Psst, you could always go with millipedes.