The movement section of the spell is just ethereal movement.
Except the spell states: "If you move up or down, every foot of movement costs an extra foot."
This is not standard for ethereal movement. This is only a feature of the Etherealness spell, since, according to the DMG, "The Ethereal Plane also disobeys the laws of gravity; a creature there can move up and down as easily as walking."
So, if "you" only refers to the caster, then only the caster is subject to this restricted movement and not any other targets.