These kits are well-intended in design, but not often designed by professional herpetologists or even biologists. It you want any of those animals you need a more professional cage. Before I start, I'll warn you it's not cheap. Set-up costs will easily be at least $100 and to maintain, will be about $100 per year.
Tree frogs like tall tanks, not long tanks. Therefore, you must purchase one of the tanks specifically designed for reptiles, not one of the generic tanks which can be turned into a fish tank, a tarantula tank, a bearded dragon tank, a hermit crab tank, etc. Due to the design and the name brand (Exo-Terra, Zoo-Med), they're pretty expensive. Over half of your cost will be in this tank. However, these tanks are pretty well designed. They have escape proof locking devices, proper ventilation which allows cold air to sink out and warm air to rise in, and even special slots to run wires through so you can have electrically-powered devices in the tank, such as a Waterfall (very cool). Tree frogs don't need very much, so a small sized tank is probably good enough, no more than 10-15 gallons. I used the large version of this kit, but small will be just right: http://exo-terra.com/en/products/habitat_kit_rainforest.php. If you think you can buy all the independent components a lot more easily, you probably have to go with a tank without all this stuff, which is hard to find. Another tank I have is by Zoo-Med and is not a kit. In addition to the tank, you need substrate, a water bowl, some climbing structures, a UVA/UVB light, and a heating light.
Substrate is important because it holds moisture and some are engineered to break down wastes. The most common are coconut fiber which are safe if ingested by an animal, but Sphagnum moss is also quite common. You basically want one that if the animal goes for a feeder and gets a mouthful of substrate, that the substrate doesn't cause blockage in the intestines (impaction) and cause death. A water bowl is important because frogs breath through their skin, so they have to keep it moist. Try and put it in shade so it doesn't evaporate in an hour. Climbing structures are important if they don't climb up glass. Sometimes glass can be rather chilly, so they'll try and climb as high as possible toward the heat to sit up there. Putting a roost under the light, about 3-4" away, will make that possible. Grapevine wood is the most popular, but it's hard to find at chain pet stores. A UVA/UVB light is important to ensure that the animal gets enough calcium. Without enough calcium, they suffer from osteoporosis (bone degradation) and often lose function of their limbs. This is commonly known as Metabolic Bone Disease (MBD). The most important part of this is picking a light which has enough range to reach to the bottom of the tank, as not all are powerful enough. The heating light is to maintain temperature in the tank. Temperature should be around 75-83 degrees, but they can take high 60's at night. Some people say to use under the tank pads, but these are less effective on animals which can climb. Food will be addressed after I take care of Fire Bellies, newts, and salamanders.
Fire-Bellies, Newts, and Salamanders are a lot more aquatic. All of them can go with the generic long tank seen for lower prices. Their requirements are a little simpler as well. They need distilled or treated water with a filter and a substrate, usually gravel. There should be a land area where a light and heater are provided, enough so they can bask. Some may not require heating (such as the Paddle-Tail Newt which actually can't live in temperatures above 70 degrees). A water heater may or may not be required depending on species. The most important thing here is really just the water quality as they'll be in or around it for most of the time. Some may not require lighting (again the Paddle-Tail Newt). They require a hiding place, but one of those Habba Huts or another half log hollowed out will work fine. No water bowl needed. Water level also doesn't need to be very high, usually no more than 1/3 of the tank height.
Food is probably the most important aspect. Pretty much all of these animals will only eat crickets. Some eat mealworms, but many think the hard shell may cause impaction. Some newts and salamanders will eat Reptomin Turtle Sticks. Crickets have to be bought from a pet store or else you run the risk of finding one in your garage with a parasite or disease which can kill the animal. You also have to gut-load them and dust with calcium powder. That basically means you feed them lots of good veggies before putting them in and buying this little calcium powder. You then shake and bake the crickets in a bag with the stuff and pop them on in. Food should be provided every 3-4 days, more for juveniles still growing. Uneaten feeders should be removed as they can harass your animal without end.