They already do make domestic appearances and have already accepted patronages, but they are not making those appearances on behalf on the monarchy.

But these appearances are not listed in the Court Circular. I just checked and neither Eugenie nor Zara are mentioned as having attended the last Garden Party - only the working royals are mentioned.

IMO, neither Beatrice nor Eugenie will ever be full-time working royals. And neither Charles nor William are going to change their stance regarding having part-time working royals.