Excadrill: It would probably not be advisable to use two ground moves, even if they serve different purposes. I'd suggest replacing Earthquake for Rock Slide as a spread move. If you can, Sand Rush Excadrill or Jolly Excadrill will be better to out-speed more Pokemon.
Stoutland: Return is better than Giga Impact for no recharge. Crunch or Wild Charge is better than Fire Fang because of higher power and coverage against ghosts. I'd also change Leftovers to Life Orb or Silk Scarf for more power.
Forretress: Good, except Leftovers is probably better than Iron Ball, because Forretress is already really slow.
Gliscor: Rock Slide is better than Sky Uppercut because of spread damage, and it still hits ice types (even though Ice types will still KO you easily). The EVs are also a little weird, I think you should just change it to 252 HP/252 Atk/4 Def.
Hope this helped!