In Dictionary > Preferences there are 65 Dictionaries listed including those listed under Other Languages even before the Shift+Click trick but no matter which were checked none appeared in the list of selected Dictionaries in the Dictionary window.
....
As to the dictionary licensing:
I remembered that I've still got a 10.13.3 volume and booted into it...
In Dictionary > Preferences I've got
33 dictionaries listed, and those that appear in my 10.12.6 Dictionary window appear in my 10.13.3 window...no tricks necessary. (Screenshot [entirely from 10.13.3] includes licensing, i.e. copyright, info.)
The licensing info you've posted is
specific to Wikipedia; Apple Dictionary is specifically copyrighted by Apple, and all others are either specifically copyrighted by or Licensed to Oxford University Press, i.e. paid content (under ordinary circumstances, anyhow).