A whole lot of mistakes I made early on taught me to always plan a tank as if the fish were full adult size. If you are a decent fishkeeper who cares and does the necessary work, they will get to adulthood. No one plans for their fish to die young.
They'll all grow. Even if they aren't violent, the tank will seem smaller and smaller and the water changes more and more demanding. Puberty will hit as they grow, and territoriality will kick in. If they are juveniles, you haven't come to that yet. The ones that will cause the most problems because of their sizes are the 2 datnoids, 1 fahaka puffer, 3 flowerhorn, 2 ropefish, 1 tiretrack eel, 4 small blue diamond parrot, and one snakehead fish.
Datnoids get huge. I've handled Fahakas that weren't just long in their bodies, but heavy. And I handled them very carefully, and not just because of their price. Flowerhorns can be viciously territorial. The ropefish will get pushed around. Tiretracks aren't bad behaviourally, but bio load? They are big. Parrots are fat fish, so a heavy bioload. How they behave depends on how deformed they are. If the mouth is too misshapen for them to bite, they are harmless. If not, then watch for the fighting to erupt in a few months. I've noticed that since they were first sold, the mouths are getting more and more functional in the ones I see in stores. The fish they were created from can be very rough customers.
The illegal snakehead should not be in any tank, but when they were legal, they were considered one fish, one tank creatures.
I am really negative here, but unless you have an entire 1970s bungalow full of water, that assemblage goes a bit beyond controversial. You have a set of fish ideal for a fishroom with 7-10 tanks in the 100 gallon and up range.