As long as you bring Ryu-Oh and Atalanta, anyone can work for you (with Sniper Shot). It is difficult to say how strong you are overall, so the answer is probably Shingen/Herc/Joan. Leftmost being for the strongest (perfect Water Glaive Grids with Shingen and Aphrodite are really strong) and the rightmost being for the weakest (Joan's damage cut can be invaluable to weaker players who struggle to survive Overdrives).