I pulled one of the the man-woman portrait shots into Photoshop and added Plus 1.80 stops of exposure compensation and it looked about right, so that shot was underexposed by almost two stops. There was no EXIF information to look at. Not sure if you have continuous lights or flashes, but you definitely need to Expose to the Right; I looked at the histogram for the shot, and the right hand part of the histogram was in the middle of the scale--indicating gross underexposure. Expose To The Right is a common catch-phrase, and is sometimes abbreviated ETTR. You can Google search it.
The histogram on the back of the camera can guide you and help you with your exposures. If your lights are at full power, you need to double your ISO value and then double it again, OR open the lens up two full s/tops, or do an ISO doubling and then open the lens up one f/stop wider to get more light in; however you do it, it looks to me like you need about two ,ore complete exposure values more light,on average, to get the exposure into the proper zone.