so it does seem like that not everything is copied from the en_us to have a proper legacy console texts like tooltips saying "inventory" instead of "open/close inventory" and also host privillages instead of "allow cheats"

here's the files for the copied en_us to other versions of english
en_nz.json
en_au.json
en_ca.json
en_gb.json

It's not necessary to copy everything, just what was modified from the vanilla translations, I ended up forgetting the ones you mentioned