The Quiet traveler: "You may equip [H][H] Melee Weapons with only 1 [H]"Quiet Traveler doesn't say "Treat All [H][H] Melee Weapons as [H]" so these abilities do stack. The Melee Weapon is still a double-hand weapon, you're just allowed to assign it to a single hand.
The Control Discipline: "While using a [H][H] Blade Hand Weapon, you may use a D8 for your combat Damage"
The control discipline upgrade requires the weapon to be used with both hands? Or the requiement is only that the weapon has the two hand icon? So, this two abilities could be come together.