1. Word that are specific to languages which serve as names for things are A-OK! We're not going to police the level of translation characters use :) The rule itself is more to prevent characters from speaking exclusively in any foreign language than the common one offered by the game mechanics.

Sooo for question #2, the same thing applies! You don't need to translate "kamikaze mission" unless you really, really want to since...well okay, you can translate it if you want because it translates awkward literally but BASICALLY you don't need to :')