Search for brand would give a level of brand authority or level of user interest in the site. It would be a factor, not a catch all.
Same the other user metrics. You do not have to have 100% sampling to come up with a statistical average with a margin for error that is within acceptable limits. Think Presidential polling data. 5% of likely voters. They get more that that amount of data from serp ctr, chrome, and sites with adsense. Then take into consideration such data that is given from second party providers such as alexa, compete, quantcast ect.
I would highly doubt they do not have these user metrics about your site unless your site is 100% blocked from Chrome Users, Alexa toolbar, no adsense, and no serps.