If you do get all the fish you mentioned your bioload with be out of this world especially when they grow to adulthood. The clown trigger is way to aggressive IMO
for any home aquarium and is moderate to hard to maintain. The emperor angel is a great idea but your tank has only been set up for 7 months and it will most likely not survive. They consider your tank well established up until over a year. The lion in my experience constantly fight with my tangs because the tangs like to bite his fins because they mistake them for food. Also, the lion will eat any small fish you have with no question and not to mention their difficulty to feed because they love live food and you don't want to be bothered with buying live ghost shrimp 4 days a week. The puffer is a great idea as well but my only problem with mine is their skin is a great holder to many parasites. Like sharks and eels the puffers skin is like sand paper and a parasite like ich will attach onto the puffer and although it's on the puffer the puffer will not be effected but some other fish might in the long run.
I would stick to your tangs and maybe a puffer and eventually after your tank has grown in age, get the angel. You may want to jump into getting all these fish but it's not the best idea. The less fish you have the more enjoyment you'll get out of it. The more fish the more water changes the more fighting the more stress and the more deaths. Your tank will look beautiful with the tangs and eventually the angel especially with the Fiji rock. Don't overstock because it will only cause more stress on you in the long run