I am struggling a little with the translation: Does Discourse choose the singular and plural based on count or total?
From my understanding, it’s usually count.
But I cannot figure out how to handle the case that count is 1 and total is 3. I get something like “1 of 3 post in this topic is published”. I can fix that by using “posts”: “1 of 3 posts in this topic is published”. But then it doesn’t work if total is 1. 
Maybe we need Message Format support for localization in this case?