Much to my disappiontment, it is apparently just not possible to get a Piplup in a Net Ball. However, to everyone who replied, thank you for your responses. I just wish we had the option to further customize Pokemon teams through personally customizable Poke Balls as well. Maybe, someday we will in possible future games, along side more trainer customization options.
On another note, does anyone know how to hatch a Piplup with 6 IVs? The most I keep getting are 5 IVs. Would giving both parents Destiny Knots (if I had another in ORAS), have any effect?