Like the topic said, if Loki had to level up one of them which do you think she would choose?
I honestly think that Gareth might be the one that she levels up to level 7. From a stats and abilities point of view he might be the best choice if Loki had to level one of them up.
His strength and endurance are almost maxed out and his skills only increase those stats even further. He seems pretty solid with his attack and defense.