@Kevin: Yes, I think that the structure of the Bootstrap theme steered me toward deploying my code in a theme.

@Mario Thank you for your helpful advice and references. After some more hammering and moving MyClass (and its interfaces) inside the module, I was able to get it working. I'll make another effort in deploying everything inside the module. Thanks again!

Thank you for your reply. I agree with and try to follow the principles you bring up. I did try to move MyClass in to the module /src dir (and updated namespace), but it didn't load either. More generally, Drupal has always separated MVC in to two places (MC in modules, V in themes) which makes it difficult to create a cohesive product that renders and functions well while doing it the "Drupal way." I understand the intent of modularity and separating the view from function, but what good is generating a data table for a user if there's no theme/view to support it?