Blue throats are reasonably hardy as well as you get a healthy specimen. Many times, they like to hide and can be extremely shy, not coming out to eat.
They are reef friendly and will work with most fish. It will go fine in the 75 with the zebra for some time. All triggers will outgrow a 75 over time, though.
Min. tank size would be a 75 to 90, but preferably a 125 minimum.