Final Cut Pro X: Green Screen Chroma Key w/Fog Machine Messup NEED HELP

So, my friends and I are filming a 30 minute short film. The ending battle scene takes place on the clouds, so we filmed in front of the green screen. To make the cloud effect realistic, I purchased a fog machine. But, the fog sort of messes up the chroma, when I say "Fill Holes" it does fill up the holes in the person, but then creates more static. I try to remove the static, the person is removed.

What I really need to know:
Should I find a way to fix it in FCPX?
Should I use Adobe After Effects to mask each frame to fit the person?
Or should I schedule a reshoot? (since I already know a date for when we're all open)

Why not just use a smoke/fog/cloud plate under your green screen footage? Or is reshooting not an option?

Reshoot. Add the fog in post.

NEVER shoot fog on a green screen! Lesson learned. It picks up way too much of all ambient light and colors, especially the chroma green.

I have successfully shot smoke (from something burning, not fog or mist) on a black background to composite over other stuff. But "smoke" is pretty dense and well define. Fog and mist are just too light and obscure for this sort of work.

There's no way you can fix this in post, neither in FCPX nor in AE. Manually masking out the persons (rotoscoping) is a drag. It will cost you much more than reshooting, and you still will have the existing smoke on the persons.

So yes, reshoot the clean key and add smoke/cloud/fog in post. You can either film the plates yourself, or you can get pre-recorded smoke/cloud/fog footage to comp it over your scene. There are hundreds of those available on the net. They're affordable, you can preview the different clips before you decide which ones you will use and they can easily be tweaked. A no-brainer.

As an example, here's a free 4K smoke clip: vimeo.com/72058568

There are some smoke affordable but very high-quality collections specifically created for FCPX:
store.pixelfilmstudios.com/plugin/stock-prosmoke
www.motionvfx.com/mplugs-23.html

- Ronny