A couple comments:
-Blackstone isn't going down to Oregon just to install HPWCs. Like others said, I'm fairly confident this is a supercharger just based on their involvement.
-55k is awful cheap for a supercharger but way too much to be HPWCs. They used to list the valuation of supercharger installations as something like a quarter million dollars. More recently I've seen it be in the 100-200k range. Maybe they've streamlined the process to make it as cheap as 55k. If so, that's great, especially when you compare it to non-Tesla L3 charging installations.
-It's definitely possible that one of these Hood River sites fell through and we'll only end up with one supercharger. The fact that they are on opposite sides of the highway gives some hope that both will go in. If that happens, I think a supercharger at Biggs Junction is unlikely in the near future. But I don't think any of this has an impact on the possibility of a Boardman supercharger.