Opreddo

Finally made my way through. So indeed Stunky switches out to Frillish when it runs out of PP for Sucker Punch. (use growl 6 times) From there, use growl 20 times, so Frillish runs out of PP and kill it with Peck. It will switch back to Stunky, use growl until you can finish it with 1 Ember. Then you should have just enough HP to tank Bergmite's Rocky Helmet when doing Reversal and for one Yanma's Sonicboom.

Same issue here