A minimalist Openbox desktop for Vim freaks

Are you the sort of person who is looking for a Vim plugin for everything? Does having to reach out for the mouse sideways cause you involuntary facial muscles twitches? Is breaking out the arrow keys with a screwdriver among the first few things you do on a new computer (after swapping Caps Lock with Left Ctrl, of course)? Then welcome, you’re among friends here.
UPDATE 2020-05-11: Updated instructions for Crunchbang++ 10 (based on Debian 10).