i personally dont see an issue with one or two of the fish with selected corals. It is the number of fish in a small tank that is a problem. If you are wanting those fish, I would try to save a little and get a bigger tank! I have kept a large golden puffer with a good sized red scorpion fish in a 72g. It had a 75g sump, and a 250 gallon skimmer. We did frequent water changes and never had problems. I say get a 75g tank at least and then you can do what you want! besides one thing you will learn is that the bigger the tank, the easier the care is. A 75g tank is much more forgiving then a 30g tank!