If u dont want buggy to be screwed by roar u can run an offensive move over protect to fake an offensive set and not let it be dead weight.
Rock slide
(yes, mono rock slide) for the most common switch in to scolipede: kamikaze flaming bird
Also nails Zapdos, gyarados-n, noivern, charizard formes, the rising Entei, dragonite, mandibuzz, volcarona, Dickpinch on the switch. It gives great neutral coverage on the tier, though unstab and abit weak.
Earthquake
While being a terrible move to use on mono-attacking set, this can thoroughly destroy heatran, dent excalibur, manectric, bisharp as well as a couple of other less common pokes like aggron (lol not really).
Beware, ferro and skarm can still screw u up, and choosing either move leaves u walled by rotomw, or flying pokemon if earthquake is chosen.
TL;DR: teammates of megawile must be able to pose an offensive threat themselves as megawile cannot do much on her own, despite receiving boosts and the like. She needs things that can force her out like rotom w, trevenant/gourgeist, heatran, skarm, rocky helm ferro, talonflame, banded infernape to be removed before she can begin her sweep. Therefore predictable partners who usually set up can choose to take the unpredictable route of actually luring out her nemeses and defeating them. Scolipede is a great partner for mawile as it lures out pokemon that threaten them both and nailing them hard with the appropriate coverage move, then baton pass the boosts to mawile or any other more suitable partner depending on situation.
Buggy @ leftovers/sash
Speed Boost
252atk/252spe/4spd jolly
Substitute
SD
BP
-Coverage move-