Mouse & Touchpad Separate Settings Missing
You have installed
libinput. It is used instead of
xorg-synaptics to manage the touchpad.
Unfortunately current Ubuntu with Unity DE does not have
libinput settings GUI by default.
unity-control-center can control only of
Another option is to uninstall
xserver-xorg-input-libinput package and use
xserver-xorg-input-synaptics that is installed by default instead.