Incorrect.
Smooth Over does not directly stack; when you use it, you search your deck for a card, shuffle the remainder of your deck, then put the new card on top. If you use a second instance of Smooth Over before drawing a card from the previous one, the second one "erases" the stacking of the first. You can Smooth Over, use the Ability on Zoroark-GX to draw two cards (one being the card Smooth Over top-decked), then use a second instance of Smooth Over and use another Zoroark's Ability to draw that card (plus the one underneath it).
Also, if you need that many specific cards, you may be better off just trying your luck to draw into some of them first. No, really: while there is a chance you'll fail to get all four from the combination above, a draw Supporter has higher utility.
Ahhh my mistake. Thank you for pointing out!