You should be fine without a heater, but get a temperature gauge and Humidity gauge so you can monitor heat and humidity to be sure its right.

Organic soil can work as long as it contains absolutely no fertilizers or chemicals. Are you able to order Eco Earth Coconut Fiber?

The frog will be fine for a month if you offer a diverse diet with a few different items offered for food. I would only offer the roaches once a month so you don't cause Vitamin A toxicity. Vitamin A toxicity is when there is a buildup of the vitamin in the frog's system and essentially poisons the frog. The same can happen with all vitamins if given them too much too often. Stay away from Mealworms and Superworms. Their exoskeleton is made of a hard chitin that the frog will have trouble digesting. They can cause an impaction which is a severe blockage of the frogs intestinal tract. Impaction can be fatal. Pinkie should not be Fed to your frog until it reaches 2.5" in length and no more than once a month. Fish should be the same. Crickets can be gut loaded by feeding them fruit and vegetables. This will fill the crickets with vitamins that will be passed on to your frog when the frog eats the crickets. Earthworms are the best feeder for frogs as a staple. This roaches would not be because they will eventually make the frog sick with Vitamin A toxicity.

Are the tanks L"x W"x H"? If so then the first tank should be ok. About the second tank, may want a different one for when the frog gets bigger, but it may still work.