Congratulations on your new frog!

If you haven't already, please read Frog Forum - Red-Eyed Leaf Frog/Red Eyed Tree Frog Care - Agalychnis callidryas

The rocks in the drainage layer shouldn't need replacing, but you will need a way to siphon water out of there as it accumulates. A picture of your tank could help people advise you.

A spray bottle is fine for misting, get a new one (don't re-use one that held chemicals). I don't keep these frogs, but the suggested minimum temperature in the care sheet here is higher than Fred recommended.

A hygrometer and thermometer would be a good idea, digital is usually preferred especially for the hygrometer. "Room temperature" is vague and can vary depending on who you are talking to.

Crickets should be dusted, they have a pretty lousy nutritional content otherwise.