totally right.

we should get rid of everything at the same time, or the build is gonna complain (as flod comments on https://bugzilla.mozilla.org/show_bug.cgi?id=1001901#c3).
But if we do it in this bug, it will involve more changes than the ones to the strings (we should also remove all appearances of it in the code e.g. https://github.com/mozilla-b2g/gaia/blob/master/apps/communications/ftu/js/ui.js#L181-186)

I don't have a strong opinion in here, so you can choose whatever you prefer, either do everything in here, or focus on the strings (except this ones as they are referenced) and open a new bug for the html+js+strings changes required.