Problem installing libinput on 16.04.2
Solution 1:
So I submitted a bug report and the response was this:
You're not supposed to have xserver-xorg-input-libinput installable, that's not possible
because it's bound to the server input ABI
install xserver-xorg-input-libinput-hwe-16.04 instead
Installing the renamed package worked. These appear to have been recently renamed which is where the confusion is coming from.