Solid team, Twinkyfist! I find that Dugtrio would really appreciate the ability to switch moves, especially with Gravity being up. That's why I would recommend a Focus Sash Dugtrio, with a moveset consisting of Stealth Rock / Earthquake / Stone Edge / Reversal. By giving Dugtrio Stealth Rock, that allows Mamoswine to use Superpower in the 4th slot, enabling it to get past Ferrothorn and Air Balloon Heatran with more ease. With a Focus Sash, Dugtrio can't be OHKO'd, allowing it to get Stealth Rock up before dying. At 1 HP, Reversal becomes extremely powerful, giving you a strong coverage move. I don't have much else to add - cool team, and good luck!