Matching subjects together in background

[jichuyeyo]

So, my current goal is trying to match these ladies with the background. I would like to adjust their lighting and color to make it better suit the background. I have already tried adjusting curves using a grey luminosity layer but they still look weird to me. I can find other pictures to use if these pictures fundamentally won't work together, but I would love not having to do that. And when I do color match, I have trouble telling which colors match and which colors don't, so I would prefer comparing point values rather than matching colors by eye. Any suggestions?