Oh, come on! Gible's finally debuting, and in an episode with "Caught" or "Get" or whatever in it? Why can't it be confirmed to have a trainer? Then it could be safe from the vultures for at least a little while...
But, anyway, unless this is a double contest, I doubt Dawn will win. If Dawn's going to try something with Piplup, after telling it to watch Grotle, might it activate its Torrent ability during the battle? That'd be a good strategy: use Bide to become really weakened, unleash a mega-Bide that does uber-damage, but at the same time activate Torrent so that Bubblebeam/Whirlpool are more powerful.
But, here's how I see this going down.
Suiren Town Contest
Appeals
Dawn-Mamoswine (Pass)
Zoey-Mismagius (Pass)
Jessie-Yanmega (Pass)
COTD-Medicham (Pass)
Round 1
Dawn vs. Zoey
Piplup vs. Gastrodon (Gastrodon wins by points)
Jessie vs. RT
Meowth vs. Random Pokemon (Meowth)
COTD vs.RT
Persian vs. RP (Persian)
Round 2
Zoey vs. COTD
Gastrodon vs. Persian (Persian wins by points)
Jessie vs. RT
Meowth vs. RP (Meowth)
Final Round
Jessie vs. COTD
Meowth vs. Persian (Meowth)
Jessie wins her third ribbon.