I would give the Planar Tracker a crack at it as there appears to be enough trackable detail to get a good solid track. Here is an example of what you are trying to do. Track the ground concentrating on the area where the foot prints are located. Paint the footprints out on the frame that you select as your reference frame for tracking. That will be your clean plate to be fed into the corner pin of the tracker. Create masks that follow the footprints, these masks will replace the the areas where your footprints are located with relevant areas of your clean plate, the rest of the scene will be the original background plate.
Here is an example of what you are trying to do. You wont need the first Planar Tracker as your background is not revealed. I was able to create the clean plate using parallax from the first tracker in that example but that doesn't apply in your case.
The example could be improved slightly by snapping the front of the mask past a few slight artifacts and holding the trailing edge of the mask off and then snapping that past the area but it's just an example of the basic workflow.
Oh and you'll need to set your Corner Pin to full raster by inserting 0's and 1's in the relevant Reference Time Positions, no need to keyframe them unless you need to adjust the corner pin.
https://drive.google.com/file/d/1gswrYw ... drive_link