Customizing the "Waiting for host to start meeting" screen

Welcome to the Zoom Community, @SWaters.

Thanks for your question! It’s particularly interesting, because I thought I really knew the answer, but after doing some research, I learned a good bit more. 

I tested the screen that appears in the following situations:

1. The Meeting is started, but the Waiting Room is enabled.
2. The Meeting is not started, and is scheduled for the current time.
3. The Meeting is not started, but is scheduled for a future date/time.

All of these generated the same screen which is similar to the one in your screen shot. In my case, I have a custom video that plays. You can customize the “waiting room”, but it’s my belief that this customization is used in all of the above situations (and maybe more that I didn’t test).

The line underneath the Meeting Title on your screen shot is customized by Zoom based in the situation. However, your ability to customize the screen is limited to the items described here:

https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0059359

Specifically, it’s not possible to customize a message per individual Meeting, as you request. 

When you are awaiting to be admitted to the meeting you are in the waiting room. And these are options to customize that screen. You can even run a short looped video.

Settings > waiting room options > customize waiting room

or at the admin level

Account Management > Account settings > waiting room options > customize waiting room