Usually yes. Your Airbnb reviews are refreshed each time you sync reviews on the listing's Reviews page, and every refresh brings across the host response as it stands on Airbnb at that moment.
There is one case where it does not. If your Airbnb review count has not changed since the last sync, Houfy skips the listing entirely and a reply you added since then is not picked up. As soon as a new Airbnb review comes in, the next sync rebuilds every review on that listing and your replies come with it.
So you do not have to finish replying on Airbnb before importing - though doing so is still the quickest way to be sure a reply is showing on Houfy.