Hi! Great that you are setting up such a nice tank! Do you have experience with keeping (multiple) tangs?
I think your tank is not quite big enough to house 5 tangs. 60 inch is enough to house the smaller ones like the yellow tang, but a bit on the small side for a hippo... You could keep a hippo if that would be the only tang in the tank. Tangs are pretty agressive and I think it will lead to problems later on.
From a different perspective, I’m not here to tell you what to do. If you like these fish so much and really want to keep them all, I will give some other tips.
Make sure you have a good read on introducing tangs as they should be put in all at once. This will of course result in a huge bioload being introduced to the tank, which should best not have to much rock in the display (concerning space to swim). So be prepared to keep up with the dirt produced by these beautiful fish!
Looking forward to see your tank!