Hey,
You really can't swap a static or still image for the moving frames of a GIF.
There are 15 motion frames in the GIF. Notice that the girl in the GIf is moving and changing her facial expressions, you would have to do a swap on all 15 frames
You could swap the eyes and nose. If you swap the mouth, then it would be the same in all 15 frames. You would end up with a GIF of the girl just shaking her head.
If this were the only face swap you did on frame 1,
it would not stay the same for the rest of the frames.
The swap would have to be moved in each frame.
Here's what the frame 1 swap would look like in frame 12 if you don't swap, move, and merge all 15 layers.
You could just copy and paste the edited face (I would use a layer mask) in order to change each frame. Then I would merge the new face with the old face in each frame.
Here are some tutorials on face swapping:
https://www.youtube.com/results?search_query=Phtoshop+face+swap