All your critters should only be fed once a day. The salamanders probably 2 or three mealworms OR beetles a day. The turtle and tortoise depending on size about a handful of greens.
The fish just a slight sprinkle per fish.
Fish will eat however much you give them and can be overfed. The rest usually only eat what they need, but there can be exceptions so you keep it at an average just in case. They should manage fine if you do that, and they will all be healthy and happy when the primary teacher returns.
Best of luck!!!
-----
**Kenn**