The Iranica article I linked above mentions document evidence from Dura Europos (1996 and 2005) along with evidence from actual Zoroastrian texts from the period, which appear to be a little more recent than what you cite above. While this doesn't settle the debate on the extent, it does seem to indicate it's likely. And while incest was commonly used as an allegation against those of other religions, in and of itself it does not rule out the possibility such as the overwhelmingly conclusive evidence for incestuous marriages in Roman era Egypt nor does it disqualify evidence from Iranian sources from this time. I would imagine my professor, a specialist in this period, would have considered these before settling on his conclusions. EDIT: In case anyone is wondering, my professor was Touraj Daryaee - and to totally shill for him, he wrote an excellent introductory book on Sassanid Persia, in case you're interested.
It's not Achaemenid, but if you want something about the Sassanids, my mentor at my alma mater was a Sassanid/Zoroastrian specialist and he's written a general overview of the Sassanids, <em>Sasanian Persia: The Rise and Fall of an Empire</em>. It appears a new edition will be out next year to account for some new research (as the current edition was published almost a decade ago in 2013), but the current edition should still be good.
Professor Touraj Daryaee has a great book on Sasanians and their Zoroastrian religion. You should read it, as it clarifies much of the confusion in his book. More sources, especially after the conquest of Islam, exist than people think. Here is the link to his book in Amazon:
Sasanian Persia: The Rise and Fall of an Empire (International Library of Iranian ... https://www.amazon.com/dp/1780763786/ref=cm_sw_r_sms_c_api_i_NJpVDbBZYAWH3
This is the most up to date book on the Sassanids.