Any tips for a mono-ghost team?

So, I allways do monoghost in all pokemon, but, what strategies can I apply here?

I just won the 6th medal, and my team is D. Charizard, D. Ambipom, D. Liepard, Sableye, Gengar and Golurk

Is there any pokemon I should recruit? Any interesting moveset for this team? A D. Pokemon ghost that is a must?