Thanks for the suggestions. To answer some recent questions:
(1) I have not manually cleaned the sensor on this camera. I've only had it 6 weeks and use had been limited until now.
(2) No UV or other filters on the lenses for any of these test shots, just bare lens.
This is very strange. I've worked extensively on manual focus to see if I can get a sharp shot, but no luck so far.
Here are my latest round of test shots.
* EF 70-200 2.8 II lens
* WB set to daylight
* shot in RAW processed in DPP as a batch with all default settings. 100% crops of JPG
* cameras mounted on tripod, wireless remote trigger
(1) M: Av, 102mm, f2.8, ISO 100
(2) 6D: Av, 155mm, f4.5, ISO 250 autofocus
(3) 6D: Av, 155mm, f4.5, ISO 250 live view, manual focus