Sony doesn't expose hotter, I do. This was about the best I could do in the field. Keep in mind that this is not a test, it is observation on two images shot under field conditions, based on in camera histograms and my experience. Doing an 1/3 bracket I could get within 1/6 stop.
You are not within 1/6 stop, the Sony is 1/2 to 2/3 hotter than the P45+. If you have a whole series of exposures, I think you could find two pairs which would be better matched. In any case, I think that the overexposure on the Sony falsifies the comparison of the shadow detail considerably.
The Phase One P45+ has 39 MP while the Sony Alpha has 24 MP so it is expected to have less detail.
Sure, but the Sony details look smudged as if there was some hidden noise reduction at play.