I've hired 11 PMs (from Associate to Senior level) at my startup, and a lot of this rings true. The one thing I'll add is the most important step in my hiring process:

After phone screen, I have the recruiter send them a case study that asks them to use my product (a social game, this works better for consumer internet, obviously) and identify the most important features for monetization and to suggest improvements to the game.

1) Because the prompt is somewhat open ended and they generally have at least a week to work on it, how much effort they put into it is a great indicator of how much they want to work at my company, which to me is one of the most important things I'm interviewing for once basic intellectual horsepower is sufficient. Responses typically range from "typed some stuff into the Word doc" to "50 page PDF with screenshots, charts and graphs."

2) That also gives a concrete basis for discussing product ideas. In addition to the obvious questions of "why do you think we implemented this feature" etc, I also often take suggestions they have for the product, and ask why they think we HAVEN'T implemented it, particularly if it's a idea we've considered in the past.