Stockpile/Curse- Just in case you don't know, Simple doubles all stat changes so Stockpile turns you into a wall and Curse is Sword's Dance and Iron Defense in one turn and minus speed.
Howl/Amnesia- I think Curse/Amnesia is a bit more reliable since it takes less time to set up but Stockpile/Howl is still cool cause'... Stockpile. Both of these do the same thing though.
Rest- To heal up.
Flame Charge- This really gives you that sweeping capability though you can still use other attacks.
I know, right! Who knew you could get this much out of a Numel! You could go for either an Impish or Relaxed nature. The EVs are really tricky since its base stats are so low but I guess HP,Defense,Special Defense,and Attack(maybe Speed.) EVs would make sense. By the way, if you thought this would be good in the metagame, it's practically indestructable in Little Cup!