I haven't kept blue spot puffers, so I'm not sure if it'll nip the lion or heniochus's fins. The niger trigger is one of the more passive triggers, so he shouldn't cause too much trouble. I'd mainly worry about the puffer nipping the lion's fins, although this could be wrong as I'm unsure of just how aggressive the blue spot is.
As far as the blue hippo goes, it may have trouble if the tank's water quality suffers due to the aggressive fish. It needs to have plenty of algae to graze on, dried seaweed a few times a week, and needs adequate swimming room. If you do get one, be sure to purchase a ground probe, and watch for signs of malnutrition and HLLE. The main issue here would be that the blue tang commonly falls victim to parasites, ich, and other infections, that may be more common in an aggressive tank. Also, blue tangs like plenty of spots to hide, so you'll have to create LR structures that give it some protection away from other tankmates.
