Shit, I always get screwed in Doubles and Triples.
Ralts, use Trick Room this time, and if for any reason the action is not completed, use Trick Room again on the second action. If you succeed on the first action, give Vulpix some of its own medicine with a Hypnosis of your own.
Turtwig, use Protect to stall the first action, unless they don't attack you, in which case use Razor Leaf to strike all three. Finish with a Body Slam on Vulpix.
Torchic, use Fire Spin to trap Riolu, and then blast it with a Fire Blast. If on either action Vulpix tries to absorb the attack, use Reversal on Vulpix instead.
Ralts: Trick Room->Hypnosis (Vulpix)
IF Trick Room fails for any reason, THEN use it again on action 2.
Turtwig: Protect->Body Slam (Vulpix)
IF you are not attacked in the first action, THEN use Razor Leaf instead of Protect(all targets).
Torchic: Fire Spin (Riolu)->Fire Blast (Riolu)
IF Vulpix tries to absorb the attack, THEN use Reversal (Vulpix).