Thanks for the detailed explanations, Damian - - I have never used FP in it’s standalone mode - I naively assumed that, when embedded within PL, it produced the same results as in standalone state.
Just a couple of points that may help;
Are you aware that you can modify the corrections that PL uses, by default, for each new image? - in your case, you could turn off NR and SmartLighting.

Your option #1 is already possible … the Windows target is “C:\Program Files\DxO Labs\DxO FilmPack 5\dfpv5.exe”

John