I used MB7 and my tank cycled in 2~3 weeks, Cad Lights 70G Artisan II,. Skimmer is for pulling proteins, etc. out of water. There may be some bacteria but I don't believe enough to chance it.
It would be dry rock. I have some marine pure media spheres from my other tank that I had thought about assisting with the cycle but I'm not sure there would be enough bacteria to initiate a good cycle?
That would be quite helpful to supply bacteria, but you still want organic matter to break down and produce ammonia, such as a shrimp, or possibly skimmate, if you want to go that route.