Don't look like gray treefrogs too me, but it is quite possible. Could also be Green tree frogs, (American). The care would be basically the same as the care of a grey tree frog, as they are very similar. Usually grey tree frogs have more of a pattern on their backs. Greens have practically no pattern other than a white stripe on their side. There are morphs of the Green Tree Frog in which the stripe is absent.