This is just my opinion, but... People will continue to power down and convert to HBD until one of two cenarios happen:
The debt goes over 10% making HBD depeg to the lower side so the conversion will no longer be 1-1. However, this creates a selling pressure which hopefully makes people stop converting Hive to HBD.
As the debt approaches 10%, people start buying HBD from the internal market and exchanges instead of converting it, and if the search is bigger than the demand, the price of HBD depegs to the upside since people will be after the future earnings of 20% APY *
*: Maybe is this what happened to the Steem Backed Dollar (SBD)? I'm not familiar to why it depegged to the upside.
I recommend ausbit.dev hive interface for accompanying the debt and other characteristics of the hive blockchain.
Thank you for the feedback, I was thinking in line with your 1st point.