My question is exactly the same as the question in Wizek's post, which went unanswered, namely that I woke up this morning and all but one of my "Okay Google" options had disappeared. I contacted Google via Project Fi's customer service and they told me they would put an engineer on it and see if they could figure out what went wrong. Very helpful. However, I'm wondering if anyone in the community has managed to solve this problem (I have a nexus 5X)?
One thought I have is to do a nandroid backup and then completely reset the device using { fastboot format userdata } , but if anyone has any less nuclear ideas I would love to hear them!