There are so many combinations that will work in arena.
The more toons you play, the better the coordination will be on your team, but the worse off your team will be for independent actions or reacting to five different opponents.

In the previous seasons, 4x elemental shamans along with 1x healer, played by someone else, was probably the most successful boxing combination.
For pvp, I doubt you could arena competitively playing more then a single class. Maybe you can, but I know 99.99% will not play two classes as well as they play 1 class.
If you're playing 1-4x of the same class, that limits your teams composition somewhat.
Also as long as you don't start to melee, follow works fine. Once auto attack turns on, follow is broken. So you want non-melee ideally. A hunter is fine, but once the opponents are in melee they switch to melee automatically which breaks follow.
If you don't want to play 4x plus 1x, you could try 3x (you) plus 1x (player 2) plus 1x (player 3). Not sure if this is an advantage through more independent action or a penalty because of less focused fire.

Experiment and see what works.