Face looks strange. Very feminine. (But I think it is a male.) I don't think those are real eyebrows. My first thought was glasses frames, but I would think there would be a glare, plus too...obvious. I think maybe another mask underneath or eyebrows painted on. Maybe they learned from BK that eyebrows can help identify, who knows. They don't look real, especially not for a male. And yes, I know some men groom, but these look almost makeup. I think the mustache is fake too. My guess is they may have been wearing a crude disguise, even under the mask.
I think it seems professional. Not SIL. Not a random contractor who came back. Not a robbery. Not a home invasion in the typical sense.
Hard to say if NG opened the door or if he broke in. Did we ever learn anything about a forced entry? Nancy Grace mentioned in one of her early shows that something about the blood seemed to suggest Nancy was upright when she left the house, that the way it fell suggested a possible nosebleed. (No link, just memory, but she was only speculating out loud anyway.)
The pictures are terrifying. It's encouraging that SG came right and said they believe that Nancy is alive.
FBI director already scheduled to be in town is nice coincidence in timing. I imagine he may stick around for a bit.