Hello,
first of all, thank you for an in-depth description of your project.
For you convenience, I could also add a simple admin page where general variable could be set as it's easy to set and also it does not effect performance in any negative way.
Since your plugin is going to work with real-time data, setting cache for responses is also not needed. The only thing that is needed for best compatibility with performance plugins is to use Wordpress coding practices for including javascript files, so they would be minified automatically.
Other than that it's very simple and straightforward plugin that is difficult to make in inefficient way in the first place!
I would be happy to do the work for you during the next few days.
If you would like any more information about me and my skills, I'm always here with an answers.
I'm looking looking forward to hearing from you.
Best regards,
Andrius