Thanks, Lefty. That helps a lot. And, yes, I need to get a couple primes in my bag. I'll double check my sig for accuracy. Right now i just have the 24-105L.
one image (woman alone) is reporting being shot @ 130mm
But I am holding still, using IS, etc. So are the subjects. In fact, Friday I took a group shot, tripod, IS turned off and ten-second timer. I still got ghosting.
exactly.
with the infinite space of the internet between us, i cannot say with 100 percent certainty that it is not ghosting. However, having taken many tens of thousands of images over 35 years time, and edited my own, as well as other photographers' work over the last 25 or so I would put money on missed focus. And i'm not a gambling man. 
I also can't say for sure that you are not moving the camera, but you would have to have super shaky hands, and likely some type of nervous condition to shake the camera/lens with the SS, focal length and equipment you list. I'm not making light of any potential problem, it's entirely possible, but you would be aware of the problem or not telling us, or just in denial.
go back and look at the full resolution images, look at the standing guy's watch, the spiky hair of the kid, the grass in both of those and the print on the shirt of the arm closest to the camera of the woman standing alone. All look sharp to me.
you are missing focus and probably not sharpening your images properly. Doesn't sound like you understand ghosting either.
