Here's one possible method
Layer 1: gradient
Layer 2: mask on white fill
Layer 3: desaturated original, set to multiply mode, layer opacity reduced to 69%
Layer 4: same as layer 3, but with inverted mask applied, set to hard light mode, opacity 100%
Please excuse the bad quality of the GIF, because GIFs don't do gradients very well.
Here's a sample showing ...