What source are you using for help? Several problems here. First, your aquarium is way to small. Second, both of these species are extremely difficult to maintain long term. Any hobbyist who needs the help of an online forum does not need to be keeping either species. Finally, neither the Trigger or Puffer or any other fish will be compatable with your choices.
If you were to have any chance at all of pulling this off, you would have to make a decision to only keep the stingray and have a species tank. Even then, you would need to buy a very small stingray and be prepared for an upgrade in tank size within a couple of years.
You should consider it a blessing to have such a large aquarium and select species which you can care for properly. If you are fascinated by fish which have "shock value", then you have plenty of other choices. How about a Moray Eel? Or maybe a species tank of 6 Volitan Lionfish? How about a Stonfish? Maybe a tank with 7 or 8 different Puffer species? You could really have some fun without supporting the wrong side of the hobby.