Hi there, I think that two of the shots can be saved in a color grading session with Color, Da Vinci or Pablo, but it’s impossible to say how to fix it posting on a forum.
However, I want to give you some suggestions for the next shooting sessions that can help you to be un a better position next time.
I. Set both cameras at the same iso and at same aperture like f4 and don’t change the f stop try to maintain the same depth of field in both cameras it helps with your visual continuity.
II. Go in the picture style menu of your camera and select to shoot in neutral mode then lower 2-3 units of contrast. This adjustment will allow you to record more tones and you can always easily add contrast in post, but you cannot successfully remove it. So even though the image look a little bit flat you are in the right spot. Footage doesn’t need to look good in your camera LCD but on a calibrated monitor later in post. This tip is really the key to pull out as much as you can from your hddslr, details in the shadow need to be visible we are not looking for solid black.
III. When you convert the footage from H264 mov to AppleProRes 4:2:2 or other video codec compare and contrast the footage “before” and “after” the conversion of the clip. It’s rare that default settings in the encoding software will do a great job. Usually, in this task you loose f-stops and background goes darker than what the original H264 shows. So try different settings tweaking the sliders (contrast, brightness, exposure) but in a very saddle way 2-3 percentage units max at the time. Moreover, change only one at the time render it and evaluate it because if you adjust more than one variable at the time you get lost. I use mpeg streamclip which is a free software for this task but you can do the same with FCP or Compressor. Hope all of this would make sense to you. Ciao!