@PrettyWingsInteresting choice. If you really want full support, I would suggest MED / SAB / SYN instead because SAB can do a lot to stabilize chain gauges. The reason I suggest an offensive role is because you will find yourself struggling to feel useful in certain combats otherwise. Having SAB as your second ability will help you find more use in the first several combats where there are fewer bonuses to chains. If you don't unlock it until later on, you won't be able to affect enemy chain at all for a while, which means if you get put into a two-person group, you're really going to struggle.
That said, I'll let you go with that choice if you want to. :)