I don't see him being a "foil", but rather as a mirrored version of Vinny, but better than him; someone who can seem at times to be similarly resourceful, single-minded, and ambitious, but who does things for the benefit of others not himself, which is the difference between him and Vinny.
If they are to ever meet and "butt heads" I reckon it would be within Quinn's story since we know that Vinny has seemingly become something of a rival for Quinn in the sense that he's doing better than her in selling the drugs. So maybe he'll offer her some sort of shady deal to help her and this is where the MC would come in to help/counsel Quinn so she doesn't go through with it. I don't, however, see Vinny being the "mastermind" of anything.