Interesting, i used vivillon in lv 40 and took enough some of the attacks on gengar, and so i attacked gengar. Afterward the vivillion got defeated and i used dusclaps's shadow sneak to end gengar.
Also i used azumarill(with pure power) and had quick claw and defeated candlelure.
About the other pokemon, i don't fully remember how i defeated them pr what pokemon she had. But i got really help by using dusclaps and murkrow's night shade.