I often freeze extras with the skins on, and then I just toss them into smoothies later.
Of course, depends on what you plan to use them for ... then you may want to slip the skins.
Instead of using Fruit Frest .... you can just dump the slices into 7-Up or Sprite (diet or regular). They don't need to sit any time, just so long as they are fully covered with the 7-UP. Then remove and freeze. If you want them to be "singles" you can lay them on a cookie sheet til frozen, then bag. I prefer to lay them flat in a bag, to save the second step later!
BTW ... the 7-Up method works perfectly to keep sliced fruit for a fruit tray from going dark! A tip I was given by a professional caterer as to how they prepare the fruit ahead for orders.