Looks like you are overweight. Depends on your system,, memory... But some have rendered armies with a half gig of ram

You can bring in one prop at a time until you choke, or you can make the front figures invisible,, render the rest,,, import it(render.tiff) as a background, make bg objects invisible,, figure visible,,, render.

This seems the quickest option to me. The lights... I cannot tell without more info.