ffmpeg -y -ss 1 -t 11 -i "/tmp/videofile.mp4" -i overlay.png -filter_complex "[0:v][1:v]overlay=0:0:enable='between(t,1,11)'" /tmp/overlayed.mp4

ffmpeg -y -ss 1 -t 11 -i "/tmp/overlayed.mp4" -vf fps=10,scale=480:-1:flags=lanczos,palettegen /tmp/palette.png

ffmpeg -y -ss 1 -t 11 -i "/tmp/overlayed.mp4" -i /tmp/palette.png -filter_complex "fps=10,scale=480:-1:flags=lanczos[x];[x][1:v]paletteuse" /tmp/final.gif