Hi 
I don't know the answer to this. Sorry you are not getting replies
from anyone at the moment. There is a big event coming up soon and
people are unusually busy preparing for that and other things.
I think the way it works is that your translations appear with the
next release of LibreOffice. Any translations that aren't done
automatically show up in English instead of your language. As you
complete more strings less and less shows up in English.
So, you don't have to complete things before people start to benefit
from your work.
Regards from
Tom 