Go Hydro+Geo (with a +1 Necromancer Ring and a +2 Huntsman Ring) for the healer and Summoner+Aero (again +1 Necro Ring is needed so you can learn blood infusion) for the damage dealer...you will jugle between Blood Incarnates (made from your healer's blood rain until you craft blood infusion) and Lighting Incarnates (made from electrified blood until you learn to craft lighting infusion).
These are the easiest builds I can think of if you are starting as a Rogue (a toppic toward which I have mixed feelings).You don't need to make a Rogue just so you can steal stuff,you can do that just fine as a Knight or Battlemage.
Also for your healer,make sure he or she has enough str to put on the chest piece of a plate armour and enough constitution to manage a shield as she will mostly toss grenades and heals,with the occasional Fossil Strike or Impalement
