So after many fails I finally manage to beat them. I changed the strategy a little bit since my lvl100 Gengar was not 1hit kill some of the pokes.
Gyarados lvl 95 - Crunch, Aqua Tail, Icy Wind, Dragons Dance
1 - Will - Lead: Gyarados - Use DD 3-4x, you will find yourself really low health, 1hit kill them all using Crunch.
2 - Koga - Lead: Gyarados - Use DD 5-6x, 1hit kill them using ice wind/aqua tail
3 - Bruno - Lead: Gyarados - Use DD 5-6x, 1hit kill them using ice wind/aqua tail
4 - Karen - Lead: Gyarados - Use DD 5-6x, 1hit kill them using ice wind/aqua tail
Here is where I found a bit of diff
5 - Lance - Lead: Gyarados - Use DD 3-4x, you will find yourself really low health, 1hit kill Charizard with Aqua.
Gengar comes into play, since I could not 1 hit kill Lance's Gyarados, and finish with psychic.
Next dragons were only using Earthquake and Gengar could easily finish them all.
No pots, No revives used, only PP berrys.
Thanks for the topic that could helped me and thats it guys, gl hf
(Sry about my bad english, feel free to correct anything, I appreciate the support a lot)