just to help people at this time please if you predection future and your including yet to be caught pokemon set it out like this
cubchoo/scraggy (just in case ash doesn't capture one)
next ash tranquill and snivy are female as is iris emolga every one else is male of unknown
finaly don't call someone prediction wrong it's unkind
.......If you insist *Confused Face as some people like myself, set it out where there is a row for ash's pokes and a row for opponent's pokes*
Ok then, Ash vs Stephan (The above post kinda ruins my whole idea but hey)
3 on 3
Ash-Leavanny Bouffalant/(Hmm, Palpitoad) Cubchoo/(Erm, Gigalith?) vs Stephan-Zebstrika Simipour Darmanitan
Leavanny vs Zebstrika-Zebstrika lands a couple of double kicks and sends Leavanny flying until it lands an energy ball. Zebstrika uses volt switch.
Leavanny vs Darmanitan-This Darmanitan has zen mode and starts off using flamethrower and focus punch. Leavanny is hurt but tries to hang on with protect. Leavanny starts powering up solar beam which prompts a switch.
Leavanny vs Zebstrika-Zebstrika evades most of the solar beam though is hit. Leavanny then uses X-Scissor on top of Zebstrika's mane to bring it down and tries an energy ball which prompts a direct overheat from Zebstrika. Leavanny is instantly knocked out. Ash is puzzled by volt switch a bit and Iris is screaming from the stadium seats: 'Ash remember me? Remember Emolga using Volt Switch?' but she is ignored.
Bouffalant vs Zebstrika-Zebstrika tries a double kick but Bouffalant manages to evade with double team and then tries a head charge which misses. Zebstrika tries a volt switch which Bouffalant takes head on with wild charge, burning Zebstrika who escapes.
Bouffalant vs Simipour-Simipour is all over the place and running around the buffalo. Simipour starts using ice beam which annoys Bouffalant who retaliates with head charge that misses. Simipour starts trying more ice beams which does more damage and annoyance. Bouffalant then uses double team to evade and then head charge directly onto Simipour, knocking it to the ground and bouffalant to its knees. Simipour gets up and tries bite but Bouffalant takes it and releases a big wild charge directly onto the weakened Simipour, who goes flying into the rock's. Bouffalant wins though is weakened.
Bouffalant vs Zebstrika-Bouffalant starts getting sick of zebstrika and starts using wave after wave of head charges which miss. Zebstrika then lands a final volt switch, shortly before switching. Ash is still annoyed while Stephan is trying to look superior.
Bouffalant vs Darmanitan-Darmanitan returns with superpower that cripples Bouffalant who tries a final wild charge which is stopped by focus punch. Stephan recalls Darmanitan so the stat drops mean nothing later.
Cubchoo vs Zebstrika-Ash smirks at an idea and Cubchoo looks playfully towards Zebstrika who he tries to sneeze on. Ash orders a lot of ice beams across the field so Zebstrika cannot run. Stephan is angry at this and orders for Zebstrika to hit Cubchoo with double kick and misses, while Cubchoo obliviously skies around the field. The crowd and Cilan aww and applaud while Iris simply smiles and does a few applauding. Cubchoo then tries ice punch onto Zebstrika which works but allows Zebstrika to use Overheat which hurts Cubchoo badly. Cubchoo gets up and uses dig which suprises Zebstrika who goes flying and then falling into the ice. Zebstrika is finally out.
Cubchoo vs Darmanitan-Cubchoo is instantly scared and cries to Ash who tells it to be brave. Iris feels sad which Cilan picks up on later. Darmanitan lets out a sinister chuckle and uses flamethrower across the field, melting the ice and giving off steam which hurts Cubchoo's eyes. Cubchoo tries to protect itself by shooting ice beam everywhere which hurts Darmanitan a bit but does barely anything and Darmanitan readies a focus punch which hits. Cubchoo is nearly down but gets back up and uses Dig. It works but Darmanitan does another focus punch while soaring into the air. Cubchoo is on the ground, getting up slowly while Darmanitan runs over, preparing a superpower which Cubchoo manages to evade and use ice punch. Darmanitan is hurt and activates Zen mode which freaks Cubchoo out. Darmanitan shoots large amounts of flamethrower everywhere while walking, making Cubchoo trying to run, but instead crawls. Ash gets an idea and tells Cubchoo to use Dig. Stephan shakes his head and orders flamethrower but Cubchoo covers the tunnels with ice beam and using ice punch onto the tunnels to make some of the rock fall. Ash then tells Cubchoo to sense where Darmanitan is and then suprise it at the last minute. The stadium is silient, and Darmanitan is nervously looking around wondering where the polar bear is. Cubchoo suprises it by emerging right in front of it's face and pushing it upwards. Darmanitan then uses physic to keep Cubchoo at one place which works but Cubchoo manages to shield itself with ice beam. Darmanitan tries more flamethrowers but Cubchoo evades them all with dig and then uses ice punches onto Darmanitan. Darmanitan is going down but needs one more dig attack which is given. Darmanitan lands another superpower directly onto Cubchoo who starts going down but uses Ice beam across the field directly at Darmanitan who cannot move. Cubchoo then runs and finishes Darmanitan off with Ice punch, suprising everyone and winning the match for Ash.
*Sigh* No feedback...

I like the idea of Ash getting Cubchoo and Stephan getting Darmanitan as they just seem really similar respectively. If Stephan had to use another pokemon, I'd say Sawk or Ferrothorn. I don't know why but I want to do one for team rocket however I am not sure they will have a big lengthy battle, maybe against team plasma? Or Giovanni vs N?