Help identifying rocks

[mbuch21]

Hi. I recently picked up a few nice rocks for the saltwater aquarium. I’m new to the rock identification game and am trying to learn the distinguishing characteristics of Fiji and Tonga in particular. Here are a few photos. Any help identifying the types of rock would be splendid, thank you!

 

[mbuch21]

Is it possible all three of these are Tonga, notwithstanding how different they appear?