That's basically identical to a care sheet for a whites or green tree frog...
Gray tree frogs are not as sensitive to temperature and humidity as tropical tree frogs. A water bowl is more of a luxury than a necessity. And it's a luxury that needs to be cleaned and changed every day, or it will become a breeding site for disease. In the wild they most likely get their water from rain and morning dew. If they get too dry, they bury themselves in moist soil.
My frogs get all the moisture they need (and probably more than they need) from being sprayed with water daily. They never bury themselves.
I've seen gray tree frogs not only resting on trees out in the open on dry days, but also once on a concrete building surrounded on all sides by sun- baked pavement. These things are probably more tolerant of heat and dryness than some reptiles...