Their care isn't really that hard. They need a 50% PWC a week. I don't think that's that bad. I mean 10% a day for 5 days. They need frozen foods and live foods (snails). Live foods only once and a while. You may feel intimidated with live foods but pond snails are fine, and they are easy to culture in a small tank. They don't even need snails to be honest, because it's suppose to wear down their teeth but DP's don't show any problem with large teeth like other puffer species. For the hex, everyone always wants something exotic but with a 5 gallon hex. your not really going to find anything, they do have some crazy colored shrimp out there.
Also dwarf puffers are 100% FW. Green spotted puffers need BW as they grow and as adults can be fully acclimated to SW.