Your gals are hungry- how are you feeding them? Make sure they are healthy before you clone or they won't root well... What nutes are you using?
Also- get the mylar OFF the planters! Walls- OK.. but too close and not smoothed-out will cause reflective hot-spots on the plant and can cause burns....
The 1st one is definitely able to be cloned and would do well if you just cut off the top 1/3 as a clone so she is about the same height as the others-- having your plants all one height is always a better option for light placement so they all get an even light-spread...
Just dip the clone in rooting hormones and place it in a soaked rapid-rooter or peat pellet... soak in cloning solution mixed per directions, then put it in a dome-- if you do not have one- use an empty clear pop bottle-- clean it out- cut the top 1/2 off... remove the cap and put the clone inside with a tablespoon or so of the water/solution-- then fit the top 1/2 of the bottle back on... put in a warm place near the lights...
should root in a week or so.
Good Luck!