Video

You can schedule a meeting with Video Off for host and/or participants, and once in the meeting (make sure you're the first one in - use a waiting room), under the Security button, you can uncheck the option to allow participants' to turn on their video.  

As far as I know, there's no way to turn off the names that are displayed in the thumbnail boxes, however there should be an option to "Hide non-video Participants" someplace, either under the More (3 dots) button in the meeting controls or the View controls in the top right corner or the meeting window.

Only other way I can think of is to use a webinar instead of a meeting, so you wouldn't see any boxes, and the participants would only see the host.