A:Answer So far, the sole answer to this question, by "uncleted", does not seem to work - saying "OK, Google, display temperature." results in the device acknowledging the command, but doing nothing on the speaker. Instead, it toggles the temperature display on my Chromecast's screensaver on.
Saying "OK, Google, display temperature on [Speaker_Name]" results in it responding that the speaker cannot display video, and that only Chromecasts and Google Cast enabled TVs can perform that function.
Will update if I find a working solution.