Isolate person, apply tone mapping to him only or dodge and burn shadows and highlights by hand.
Add cyan to entire image, this also adjusts the water/sky color.
That is the basic adjustments that I see. I don't think the background was selected and processed separately. I think most of the processing was done on the isolated subject.
Note: Without ...
These samples simply look washed out from flare to my eyes. The lens was sharp but the sun is fogging the image. If you wanted to replicate flare, I believe Tiffen DFX 4 has that option and Color Efex Pro 4 has that option.
To combine smooth and sharp in Lightroom I would use a reduced clarity setting (midtone contrast) combined with higher sharpening settings (edge contrast). It may be more beneficial to apply them selectively with the adjustment brush rather than the global sliders.
If your images simply had a magenta cast, then simply adding in some green would balance it out and you could be on your way. Unfortunately, you are not so lucky.
Your images are magenta in color because the other dye layers in the film have broken down. You have magenta information but have lost the cyan and yellow. Simply adding green will not suffice.
Given the average luminance value of each frame L1 and L2, you can calculate the ratio of the exposure values EV1 and EV2 as
EV1/EV2 = log2(L1)/log2(L2)
And see Wikipedia for more details on this formulation.
For anyone else who stumbles across this question, I found the FiveK dataset (from MIT/adobe) to be quite useful: https://data.csail.mit.edu/graphics/fivek/, in addition to the answer posted by xenoid.
This looks like the permanent "play raw" contest on pxls.us: someone submits a raw file, and the site patrons have a go at it with their favorite tools. It is customary to have at least a summary of the processing with the submission but often people post the "recipe" file.