Yes they sing on Zoom. My family really gets into it. The music gets off when the wi-fi glitches for the brother that's hosting. This happens on a regular basis.
Witnesses are also dressing up, some to different degrees. Most brothers do coat, shirt, and tie. What's on below varies. Sisters are doing the makeup, blouse, and the hair! What's below, who knows? No one in my family puts on their shoes. I notice that more and more cameras are off one year later.
For the Zoom convention, it's full dress, minus the shoes, the badge is on. The shoes are put on when they go outside for the pictures for "The Best Convention Ever!"