All you need is an aux cord to plus in to the projector straight to the speaker. 

If you are not getting a picture what so ever from your phone its most likely the cable you are using to go from your phone to projector would recommend getting the apple certified lightning to hdmi 

The mini projector doesn’t play Netflix. It doesn’t allow it 

The longer Flange distance lens to the shorter Flange distance camera, then could use the infinity focus.
but if the shorter Flange distance lens to longer Flange distance camera, then could not use the infinity focus, you can focus on a limited distance.
the position of the infinity mark 【∞】of the telephoto lens or super telephoto lens is shifted slightly to the positive side to enable focus adjustment even when focus shift is caused due to temperature changes.The shift range is denoted by an L-shaped line, Be sure to check the focus through the viewfinder even when you shoot at infinity. 

Yes, it can. You just need to install it according to the installation steps in the user manual. However, if you install it on the ceiling, the picture on the monitor will be upside down, because the camera is installed upside down.