I remeber ty lee, I think we could go with the melee controller.
As for the Koshi warriors, tehy could be fluffed up rangers or fighters, they don't seem to have any special skill
What do you think of this:
Earth bender Class features:
Earth rune: You can mark every enemy around you as a free action. The mark last until the endo of your next turn.
Stability of the Earth: When an effect forces you to move—through a pull, a push, or a slide—you can move 1 square less than the effect specifies. This means an effect that normally pulls, pushes, or slides a target 1 square does not force you to move unless
you want to. In addition, when an attack would knock you prone, you can immediately make a saving throw to avoid falling prone.
Earth Omniscience: You gain tremor sense of the 10 squares around you, detecting invisible creatures, and other concealed creatures as if you have line of sight, without needing to make a Perception check.
Choose one of the following Links with Earth:
Earthstrength: You can use your Constitution modifier in place of your Dexterity or Intelligence modifier to determine your AC.
Earthwise: While you are not wearing heavy armor, you can use your Wisdom modifier in place of your Dexterity or Intelligence modifier to determine your AC.
Basic Earth Bending:
Minor
Ranged (10) blast (3)
You can perform a minor earth bending, like turning rock into loam soil, or soil into rock or mud; creating a stair of rocks, moving rocs from one place to another, create a small bridge, morph earth into a rough shape. You can't attack with this power, the only combat action you can perform is to create difficult terrain when fighting over loam soil, turning it into mud or sand.