No triggerfish with sharks, unless you have a couple thousand gallon tank. Triggerfish are aggressive fish, and love eating.
They will spot the cartilage on the shark, and go right in, and start eating. They will also pick on the fins of the shark. Now since you want to switch your 350 to aggressive w/ triggers. You can keep many triggers in there. I would reccomend the peaceful ones, such as the male blue jaw, pink tail, or sargassum. Now since you have such a large tank, you can keep more aggressive triggerfish, such as clowns, Crosshatch, or even Queens. If you get one of the more aggressive triggerfish, you will need to get a less amount of triggerfish. List me types of triggerfish you want, and other fish you want, and I can tell you what fish you can keep together. Good Luck!