The Papa John's Special Garlic Sauce is essentially a margarine spread with natural and/or artificial garlic and butter flavors. When I was researching this subject, I came across many butter (natural and/or artificial) flavorings that had their origins in the popcorn food sector. I don't recall seeing any such flavorings that also included garlic flavoring (they may exist but I don't recall any) but the garlic part is fairly easy to solve.
Just as Norma demonstrated in the thread at http://www.pizzamaking.com/forum/index.php/topic,25844.0.html
, it is possible to take a commercial butter flavoring, such as Whirl, and combine it with a margarine spread to come up with something that is acceptably close to the PJ Garlic Sauce, even if the final formulation does not fully satisfy the PJ Nutrition Facts. The part of the PJ Nutrition Facts that usually comes up short is in the fat and trans fat areas. As you may know, trans fats are vilified in today's health and nutrition environment, and many food processors go to great lengths to remove trans fats from their products. Many of the commercial butter flavorings are fairly high in fats and can have levels of trans fats that the FDA requires be disclosed. PJ has managed to keep the trans fats at levels that do not require disclosure (that is, the trans fat entry is zero).
As it so happens, the Orville Redenbacher's Popping and Topping Buttery Flavored Popcorn Oil that you mentioned has zero trans fats. That is because the oil is pure soybean oil, not hydrogenated or partially-hydrogenated soubean oil. On the other hand, the total fats in that product are fairly high and, when combined with a margarine spread (such as the Parkay Squeeze or other margarine spread), will place the final product outside of the PJ Nutrition Facts. But unless you are trying to avoid trans fats or high fat levels in general, that is something I would not worry about. So, in your case, you might try adding some of the Orville Redenbacher's Popping and Topping Buttery Flavored Popcorn Oil to a margarine spread, along with some dry garlic powder, and see if you like the results. In concocting such a sauce, you will want to be sure that the final texture approximates the PJ Special Garlic Sauce as much as possible.
If you are interested in clones of the PJ Cheesesticks, you might want to take a look at the thread at http://www.pizzamaking.com/forum/index.php/topic,25603.msg258088.html#msg258088
. With what is reported in this thread, and in the two threads referenced above, I think you should be able to product a credible PJ clone pizza, clone pizza sauce, clone cheeseticks, and clone garlic sauce that are better than what you will find at a PJ store itself.