My wife & 12 yr old stepdaughter just received an update at the DHS website, as well as text messages: their EAD & AP's were approved Dec 10, yay!
We have received an RFIE on Nov 5, which was a request for my 2017 tax return (I only submitted the extension form with the AOS/EAD/AP package). Mailed the return to them on Nov 20, and AOS went to "Ready to schedule interview" on Dec 5.
We were worried that the RFIE might reset the clock or significantly delay the EAD & AP, but looks like both were approved pretty quickly after the response to RFIE was received. I'd read elsewhere that RFIE for tax returns wouldn't hold up the process or reset any clocks, provided the returns were sent in quickly in response, and that was true for us.
Now just waiting for the AOS interview backlog at San Francisco, for the interview to get scheduled.