We can specifically look for explanations that rule psi effects.
If the Moon is near Venus tonight, it was pretty close to it last night. So if you observed the Moon the night before, it is plausible that you would correctly imagine it close to Venus in your dream. As for the Arabic BBQ, perhaps you smelled the food. It is common to incorporate sensory experiences into dreams. A stray breeze might have brought the smell to you, even from a remote part of the building's roof, even for just a short time, and even at a level which would not be noticed consciously. The food might have smelled Arabic, or you might have known that there were Arabic people living in your apartment building.
For the second case, where you and your friend appeared to share the same dream, it is possible that you had similar dreams influenced by some earlier shared activity or discussion. Also, in describing your dream to your recently-awakened friend, he may have imagined your description so vividly that it overrode his memories of what was actually only a slightly similar dream. Our memories of dreams are often sketchy and it is easy to imagine that they might be altered somewhat.