Here is some info I have posted before (below). My opinion of red eyes is as long as you start the tank with heavy planting & everything has been cycled...there should be few issues. Make sure you start with maybe 1 or 2 to see how they acclimate then add 1 or 2 more. It sounds like you have a plan just make sure to quarentine the little guys & buy from someone with a good reputation for RETF. And post your setup I love to see other people's ideas! Best of luck!
“Temperature/Humidity: Red-eyes thrive in a temperature range of 75 to 85F, with a drop of up to ten degrees at night. Humidity is a controversial subject with these frogs. During breeding, they prefer the humidity level around 90 percent, and some hobbyists keep them this moist all the time. Others, citing that the frogs experience lower humidity over much of the year, keep them between 60 and 75 percent relative humidity, raising it during the summer.
Housing: Although Red-eyes do not need large terrariums, they do need tall terrariums. The ideal terrarium would he taller than it is long and wide. A tight-fitting screen top is necessary if you use an aquarium as your cage. To maintain proper humidity, you may want to cover a small part of the screen, but keep a substantial area open to the air. These are not territorial frogs, but they still should not be overcrowded. As a ruIe-of-thumb, house no more than a pair or trio for every ten gallons of volume in the enclosure. The enclosure for these frogs should be quite complex, allowing them to climb, hunt, and hide as they would in nature. This means incorporating plants (live are preferred), branches, cork bark. and a substantial water bowl into the decor.”
http://www.redeyedtreefrog.com/Red-Eyed/red-eyed.html