will directv stream stream nba league pass games

Well neither of the apps are supported by the service anyways. Listing of supported apps is located here

I don't think it is a question of whether the Directv box supports these apps. If you sign up for NBA League pass via Direct stream you will be able to stream live games on Direct Stream and you can watch live and archived games on any device that supports the NBA League pass app.  When you sign on to the NBA League Pass app for the first time after purchasing NBA League pass from a new TV provider you have to provide the app with you tv provider (in my case Directv Stream), your direct stream account id, and your directv stream password so the NBA League pass app can confirm that you purchases League pass from Directv stream. If I want to watch HBO-Max using the HBO app I would have to do the same type of verification. I might want to use the HBO app even though I can stream HBO on Directv Stream because the HBO app might have a better interface than Directv Stream does. The same verification process goes for the Tennis Channel.

I think the same rule applies for NBA League pass as the NBA channel. If you want to watch the NBA channel on a streaming device like ROKU you need to "subscribe" to a TV provider package that offers the NBA channel.