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In short, to install Compiz:
Compiz 0.9 series (includes autostart for Xfce and MATE):
sudo pacman -S compiz-manjaro
reboot
Compiz 0.8 series (includes autostart for Xfce):
sudo pacman -S compiz08-xfce
reboot
Compiz 0.9 series + emerald + fusion icon:
sudo pacman -S compiz-manjaro emerald0.9 emerald-themes fusion-icon0.9
reboot
Compiz 0.8 series + emerald + fusion icon:
sudo pacman -S compiz08-xfce emerald08 emerald-themes fusion-icon08
reboot