Has anyone found a Wingull holding a Lucky Egg or is it just Pelipper? I dunno if it's worth surfing without using Sweet Scent and stealing from the Wingull or not.
Like others have said, Undella Town's water has 100% chance of encountering a Wingull/Pelipper horde every time you use Sweet Scent, but the Pelipper know Fling. You could stop them by using Imprison with a Pokemon that also knows Fling - it stops other Pokemon from being able to use the same attacks as you.
As for what Pokemon can learn both Thief/Covet/Switcheroo/Trick, Imprison and Fling, and also have the ability Frisk, it seems like it's only Duskull which only has Frisk as its hidden ability so we can't get it. :/
Just gotta hope the Pelipper doesn't use Fling for now.