These don't look very realistic. I can't figure out a way what can be fixed now. First I tried a simple fox and warm colors, then longer hair so it looks part of shirt and man. But still composition don't look realistic. Is there anything obvious that can improve it a good deal?
Hair nor beard do not help if geometry, perspective, colorfulness nor light do not fit.
A shadow on the collar is inserted. It's the masked curves layer.
The saturation levels on the head and suit are adjusted.
The collar must be wider for thicker neck. It's warped. The long nose must be near, it cannot be in the background. Heavy spherizing is applied to pull the face forward.